Floyd's questions about wattage

[Floyd R Turbo]

No, you still don't have it right.

A double sided 1 cube/day screen would be 3x4 and would need 12W of CFL split between both sides (6W per side)

A single sided 1 cube/day screen would be 6x4 and would need 12W of CFL all on one side. If you had 2 3x4 screens, then each screen would need 6W on one side.

Wattage stays the same.

The physical surface area of growth substrate stays the same. On a double-sided screen, you actually have 24 sq in of growth area. For a single sided screen to have the same capacity, you need to have the same growth area, but since you are only using one side, the dimensional area of the screen must double.

The reason the screen sizing guideline isn't geared around physical growth area (surface area) is that it gets confusing. It's easier to just talk about length x width and leave it at that.

[acorral]

From SM original post:

An example VERTICAL waterfall screen size is 3 X 4 inches = 12 square inches of screen (7.5 X 10 cm = 75 sq cm) with a total of 12 real watts (not equivalent) of fluorescent light for 18 hours a day. If all 12 watts are on one side, it is a 1-sided screen. If 6 watts are on each side, it is a 2-sided screen, but the total is still 12 watts for 18 hours a day. This screen size and wattage should be able to handle the following amounts of daily feeding:

1 frozen cube per day (2-sided screen), or
1/2 frozen cube per day (1-sided screen), or
10 pinches of flake food per day (2-sided screen), or
5 pinches of flake food per day (1-sided screen), or
10 square inches (60 sq cm) of nori per day (2-sided screen), or
5 square inches (30 sq cm) of nori per day (1-sided screen), or
0.1 dry ounce (2.8 grams) of pellet food per day (2-sided screen), or
0.05 dry ounce (1.4 grams) of pellet food per day (1-sided screen)

[Floyd R Turbo]

You just confirmed my point. In that feeding equivalents list, it says a single sided screen has half the capacity of a double sided screen. It is just another way of staying that a single sided screen needs to be twice as large as a double sided screen in order to equal the filtering capacity.

Putting all 12w on one side would just increase the intensity to the "high light" level, meaning you could (potentially) only run them 1/2 the time per day. It does not increase the screen filtration capacity.

[acorral]

So you agree that you need twice the watts for the same cube capacity if you do it single sided? That was my initial statement

As you said you need ti double the size and if you double the size you need to double the light

[Floyd R Turbo]

No, wattage is directly related to capacity, as is screen size (physical area).

Going by the "standard guidelines" for a 1 cube/day screen, a double sided screen is 12 sq in with a total of 12W of light on it, split between both sides. A single sided screen would be 24 sq in, with 12W of light on it, all on one side.

The true method of screen sizing is actually based on the surface area, not the dimensional area. A 1 cube/day double sided screen, 3" x 4", actually has 24 sq in of growth surface - 12 sq in on each side. The watts/sq in is actually 0.5 (6 W on each side, each illuminating 12 sq in). So in order to get the same light coverage on a one-sided, 1 cube/day screen, you need to illuminate a total of 24 sq in of surface growth area with 0.5 w/sq in, which is 12W total. This is all for the "normal" light level per the "standard guideline".

The reason we don't talk about growth surface area, but instead talk about dimensional area, is because it is much less confusing.

[acorral]

Sm's original post talks about half capacity for a single sided screen with constant wattage and same size, not what you are saying...

Based on what you are saying how many total watts would a 3x4 screen requires?

[Floyd R Turbo]

The original guidelines:

http://algaescrubber.net/forums/showthread.php?65-ALGAE-SCRUBBER-FAQ



Scrubber Quick Guideline:

0.5 actual (not equivalent) fluorescent watts per gallon MINIMUM [0.13 watts per liter].
1.0 actual (not equivalent) fluorescent watts per gallon for HIGH filtering [0.26 watts per liter].
1.0 square inches of screen per gallon, with bulbs on BOTH sides (10 x 10 = 100 square inches = 100 gal)
[1.64 square cm per liter]
2.0 square inches of screen per gallon, if vertical but lit on just ONE side. [3.28 square cm per liter]
4.0 square inches of screen per gallon, if HORIZONTAL [6.56 square cm per liter].
1.5 actual (not equivalent) fluorescent watts per gallon if HORIZONTAL [0.4 watts per liter].
18 hours of lights ON, and 6 hours of lights OFF, each day.
Flow is 24 hours, and is at least 35 gph per inch of width of screen, EVEN IF one sided [60 lph per cm].
Very rough screen made of roughed-up-like-a-cactus plastic canvas.
Clean algae off of screen every SEVEN (7) days NO MATTER WHAT YOU THINK.


The more recent guideline is what you posted. I believe there is an error in this statement...



An example VERTICAL waterfall screen size is 3 X 4 inches = 12 square inches of screen (7.5 X 10 cm = 75 sq cm) with a total of 12 real watts (not equivalent) of fluorescent light for 18 hours a day. If all 12 watts are on one side, it is a 1-sided screen. If 6 watts are on each side, it is a 2-sided screen, but the total is still 12 watts for 18 hours a day. This screen size and wattage should be able to handle the following amounts of daily feeding:

...because it does not make sense that a single sided screen would need to have 2x the light on it and be the same (dimensional) size, yet still only have 1/2 the filtering power. Nowhere in that above statement does he say that a one sided screen with all of the light on that one side makes the capacity double so that it equals a double-sided screen of the same size.

This has always been the rule. I think he just mixed up 2 methodologies here - the single sided screen, and the high wattage technique. The high wattage technique allows you to run the lights less hours (provided that all the light is captured by the screen) but does not increase capacity.

[acorral]

Less capacity on a same size screen with same wattage on just one side is because roots die faster

http://algaescrubber.net/forums/showthread.php?1419-New-sizing-guidelines&p=13609&viewfull=1#post13609


If all the watts are on one side, you can feed half as much, because the roots die faster.

As far as I understand and makes sense to me is that light is related to size no matter if one sided or double sided, the algae on that amount of space requires that light, but uf you only light one side roots die faster...

SM... Any word on this?

[SantaMonica]

If 1-sided, it needs twice the light for the same X by Y screen.

[Floyd R Turbo]

That's news to me. When did you decide to change that recommendation?

This still doesn't change the filtration capacity too, does it? I'm assuming not.

[SantaMonica]

No change.

[acorral]

Just as a summary for answering to celtic_fox:

-One 3x4 screen, 12 watts of light in one side, 1/2 cube
-One 3x4 screen, 12 total watts of light (6w each side), 1 cube
-Two 3x4 screens, 12 watts on one side of each screen (total 24 watts), 1 cube

Making it double sided doubles energy efficiency in terms of cubes/day per watt

[Floyd R Turbo]

No change.

What do you mean - I asked 2 questions

1) That's news to me. When did you decide to change that recommendation?

2) This still doesn't change the filtration capacity too, does it?

[SantaMonica]

Making it double sided doubles energy efficiency in terms of cubes/day per watt

Yes. It's all about keeping the roots alive.

[Floyd R Turbo]

Lets get this straight. over a year ago, I posted this update to the Algae Scrubber Basics.


Big Basic Change #1 - Screen Size

Originally, the standard method used to calculate the screen size required was based on the size of the tank. Around September 2011, that method was revised to be based on feeding amount. This is a very important change, because not only does it mean an Algae Scrubber screen is more appropriately sized, it also means you will get better growth results. As it turns out, bigger is not necessarily better when it comes to your algae screen – the algae on a screen that is too large compared to the amount being fed will become nutrient deficient over time as the algae will want to grow across the entire screen. Concentrating this algae growth down to the appropriate size in accordance with the amount fed means you will typically get more green growth, and green hair algae is what filters the best (and smells the least, I might add).

The good news here is that this means that in most cases, you can get away with a significantly smaller screen, and guesstimating your bio-load specific to your system is completely unnecessary.

Once you figure out your available flow, then it's time to figure out your optimal screen dimensions.

There are 2 ways of looking at this: square inches based on length and width dimension, and square inches based on illuminated surface area. The latter is technically more accurate, but since most people light both sides, the former is usually referenced.

The new rule is based on cube-equivalent amount of food fed daily, regardless of how many gallons you have in the system. You need 12 square inches of screen illuminated on BOTH SIDES with a total of 12 watts of fluorescent light for 18 hours/day for each cube-equivalent fed into the system per day. That means 6 watts per side of real wattage, not equivalent wattage. LED wattage is addressed separately as it has a different set of rules.

The cube-equivalent is defined as any ONE of the following:

1 frozen cube
10 pinches of flake food
10 square inches (60 sq cm) of nori
0.1 dry ounce (2.8 grams) of pellet food
3.25 mL of liquid coral food

If you feed something else and are having a hard time determining the cube-equivalent, then take the daily amount of food, put it in a blender with some water and puree it well, then strain it using a coffee filter (or a rotifer sieve if you happen to have a spare one laying around) and pour the food into an empty Ocean Nutrition or other cube-type food tray, and you will have the cube-equivalent for that amount of food.

If you light the screen from only one side, double the dimensional measurement of the screen; light requirement is the same, it’s just all on one side.

For a non-vertical screen, double the dimensional measurement again. Any screen that is not 100% vertical is treated as a horizontal screen (even if it’s only slightly slanted). This is because of the channeling properties inherent to a slanted or horizontal screen; there is an immediate loss of efficiency when the screen is non-vertical.

So, just so we're 100% clear on this:

Vertical, lit from both sides: 12 square inches of screen material per cube of food per day, 12 watts of light split between each side.

Vertical, lit from only one side: 24 square inches of screen material per cube of food per day, 12 watts of light on one side.

Non-vertical: 48 square inches of screen material per cube of food per day. Lighting must increase by a factor of 1.5 (discussed in the lighting section). In this case, a MINIMUM of 18 watts of light is needed, preferably much, much more.


Are you telling me now that this was incorrect?

[Floyd R Turbo]

I've been going over this through several thread and I guess I just completely missed the change in recommendation for single sided screens. I guess this is because I never bother with single sided screens. Essentially, the single sided screen recommended sizing guideline went from doubling the area and moving all the light to one side, to leaving the screen the same size and doubling the light density, and cutting the capacity in half. Just another way of looking at it as far as the capacity goes, but the flaw I see is doubling the light. I guess it tends to make sense on one hand, i.e. trying to keep the roots alive longer. The old guideline basically said if you take the light off one side of the screen, it halves the capacity - perhaps that was the flaw, because of root dying faster, it was actually less than half the capacity. Now the new one (Sep 2011, hardly new) says double the light on one side, but it's still half the capacity.

To me, that change in the guideline was never emphasized and never made very clear. Or else I would have been giving different advice to many people over the last 18 months regarding single sided screens. Then again, maybe I really never paid much attention to single sided screen guidelines.

[SantaMonica]

Been no change. Moving the watts from 2 sided (6w + 6w) to the 1 side, is doubling the watts (12w) on that one side. Area stays the same (12 sq in). Filtering is cut in half (1/2 cube).

[Floyd R Turbo]

Previous guideline:


Vertical, lit from only one side: 24 square inches of screen material per cube of food per day, 12 watts of light on one side.

That is for a 1 cube/day single sided screen. If you were to make a 1/2 cube/day one sided screen, it would just be half the area and half the light.

Now:


...doubling the watts (12w) on that one side. Area stays the same (12 sq in)...

This is for a 1/2 cube/day single sided scree. This is half the area and 2x the light density, or the same amount of light (compared to the previous guideline).

Am I going completely batsh-t crazy here, or am I the only one that sees a difference between these two guidelines. My point is that this was a change and IMO no one picked up on it. Anyone who looked at these fresh (meaning no experience with the old guidelines) would have never noticed the difference.

[cdm2012]

This is confusing. 1/2 cube feeding on a single sided screen of 12 sq. in. requires 12 watts of light. So what would 1 cube of feeding on a single sided screen require? 24 sq. in. with 24 watts of light?!?

[Floyd R Turbo]

The old guideline would say that a 1 cube/day screen would be 24 sq in with 12W of light on one side.

The revised (sep 2011) guideline, as I now read and understand it, says 24 sq in with 24W on it.

Also, since this makes it a "high light" screen (on one side), there is no applicable high-light rule for single sided screens

[cdm2012]

Following this rule for a 1/2 cube, would the screen size then stay 24 sq. in. lit with with 12W on each size for 1 cube?

[Floyd R Turbo]

Well basically you would have a double-sided screen with 1/2 of the necessary light intensity. So in that case, yes you would have a 1 cube/day screen, as the overall light intensity is the thing that limits the growth capacity.

When I see people's builds that are under-lit, this is how I explain to them the limitations of their setup, just so they know what to expect. For instance, if you have a 10x10 screen with one 23W CFL on each side, that's really not an 8 cube/day screen (100/12 ~= 8.3), that's a 4 cube/day screen, because 46W / 12 ~= 4.

[cdm2012]

The math involved would be completely changed for everything if we were to continue this formula for screen size and lighting.

For example we have determined
1/2 cube=12 sq. in. screen, 6W on each side if two sided, 12W on one side if single sided.
and if you double your feeding to 1 cube then: 24 sq. in. screen, 12W on each side if two sided, 24W on one side if single sided.

But the rule would have to continue if you were to double that feeding to 2 cubes and so on.
If you double that feeding to 2 cubes then: 48 sq. in. screen, 24W on each side if two sided, 48W on one side if single sided.
If you were to double that feeding to 4 cubes then: 96 sq. in. screen, 48W on each side if two sided, 96W on one side if single sided.
If you were to double that feeding to 8 cubes then: 192 sq. in. screen, 96W on each side if two sided, 192W on one side if single sided.

I've changed the formula for the AScalculator (https://public.sheet.zoho.com/public/cdm2013/ascalculator-xls-1) to reflect SM's rule and the above set of parameters were reset to the above examples. Would this be right?!?!

[Floyd R Turbo]

Hold up man.

The only difference in the calculation has to do with a single sided screen now requiring to have 2x the concentration of light.

A double sided 2 cube/day screen is 24 sq in with 12W on each side (24W total).
A single sided 1 cube/day screen is 24 sq in with 24W on one side (24W total).

Does this make sense?

See this is where the confusion lies.

Previously, it was easy. Screen size (capacity) and wattage were in synch. The old rule was 1 sq in of screen per gallon, and 1W of light per gallon. 100 gallon, 100 sq in of screen, 100W of total light (50W on each side). Then, if it was single sided, you needed the screen size to double, and all of the light would be on one side. So 100g, 200 sq in of screen, 100W of light, all on one side. Continuing on, for horizontal, 100g, 400 sq in of screen, 150W of light.

The new guideline disconnects the tank volume, but wattage and screen area are still related. Now the wrench is that necessary wattage for a single sided screen, according to the 9/2011 change, is now 2x the LxW measurement. A double-sided screen is 12 sq in per cube of food per day, lit by 12W total (6 on each side). A single sided screen is 24 sq in of screen per cube of food per day, lit my 24W of light, all on one side, which is twice the concentration of light as a double sided screen. It is presented as 12 sq in of screen per 0.5 cube of food per day, lit by 12W.

I'm glad that someone else at least understands what I am getting at here.

Look at this from a "light density" perspective, and break it down by actual growth area instead of dimensional area.

A double-sided 1 cube/day screen is 12 sq in (L x W) but has "growth surface" on both sides: 24 sq in of area to grow algae. You are supposed to put 12W total light on this (normal light level, not the "high light" level). That is 12W/24 sq.in. or 0.5 W/sq in of growth surface.

The 9/2011 guideline states that for a single sided screen of the same (dimensional) size, 12 sq in, you still need 12W of light, but all on one side. That is 12W / 12 sq.in., or 1.0 W/sq in of growth surface. This is double the light density/intensity when compared to a double-lit scrubber.

I'm not saying it's wrong. I'm saying it's confusing. I'm saying it was not directly emphasized when it was recommended. I can see why it does make sense, stronger light would keep roots alive longer. It could also photoihibit a lot easier, especially on start-up, and especially with LEDs.

It also does not jive when the rule is expanded to horizontal screens, because the prior recommendation for horizontal (or rather, non-vertical) was to make the screen 2x the size of a single-sided screen (4x the size of a double-lit screen) and increase the wattage by a factor of 1.5x. This would put it below the recommended light density of a single sided screen, according to the 9/2011 change.

Personally I think the horizontal light density should have doubled that of the single-sided total, leaving the same light density for all orientations of growth surface, across the board. That is the factor that makes the recommendations consistent - wattage per unit of physical growth area, not wattage per dimensional (L x W) area.

[cdm2012]

Ok, I think I'm starting to get it. I'll work on the changes

[cdm2012]

I'm hoping I did this right. I went ahead made the necessary changes and I simplified some other things. I got rid of the "high light" option and I removed the horizontal info. It was adding to the confusion. Algae Scrubber Calculator (https://public.sheet.zoho.com/public/cdm2013/ascalculator-xls-1)

[SantaMonica]

Putting all 12w on one side would just increase the intensity to the "high light" level

1 watt per square inch is not high, it's minimum.

[acorral]

I find this text to be the clearest form to explain it:


An example VERTICAL waterfall screen size is 3 X 4 inches = 12 square inches of screen (7.5 X 10 cm = 75 sq cm) with a total of 12 real watts (not equivalent) of fluorescent light for 18 hours a day. If all 12 watts are on one side, it is a 1-sided screen. If 6 watts are on each side, it is a 2-sided screen, but the total is still 12 watts for 18 hours a day. This screen size and wattage should be able to handle the following amounts of daily feeding:

1 frozen cube per day (2-sided screen), or
1/2 frozen cube per day (1-sided screen), or
10 pinches of flake food per day (2-sided screen), or
5 pinches of flake food per day (1-sided screen), or
10 square inches (60 sq cm) of nori per day (2-sided screen), or
5 square inches (30 sq cm) of nori per day (1-sided screen), or
0.1 dry ounce (2.8 grams) of pellet food per day (2-sided screen), or
0.05 dry ounce (1.4 grams) of pellet food per day (1-sided screen)

[Floyd R Turbo]

I find this text to be the clearest form to explain it:

Andres, I am not trying to state that the current guideline is wrong. I am just trying to make the point that it is a change from the previous guideline. How can I be the only one that sees this?


1 watt per square inch is not high, it's minimum.

...and my point, again, is that this is different than the original guidelines. I don't know how else to explain this again, except to keep explaining it the same way. I am completely beside myself.

Again.

Old (obsolete) guideline

http://algaescrubber.net/forums/showthread.php?65-ALGAE-SCRUBBER-FAQ


Scrubber Quick Guideline:

0.5 actual (not equivalent) fluorescent watts per gallon MINIMUM [0.13 watts per liter].
1.0 actual (not equivalent) fluorescent watts per gallon for HIGH filtering [0.26 watts per liter].
1.0 square inches of screen per gallon, with bulbs on BOTH sides (10 x 10 = 100 square inches = 100 gal)
[1.64 square cm per liter]
2.0 square inches of screen per gallon, if vertical but lit on just ONE side. [3.28 square cm per liter]
4.0 square inches of screen per gallon, if HORIZONTAL [6.56 square cm per liter].
1.5 actual (not equivalent) fluorescent watts per gallon if HORIZONTAL [0.4 watts per liter].
18 hours of lights ON, and 6 hours of lights OFF, each day.
Flow is 24 hours, and is at least 35 gph per inch of width of screen, EVEN IF one sided [60 lph per cm].
Very rough screen made of roughed-up-like-a-cactus plastic canvas.
Clean algae off of screen every SEVEN (7) days NO MATTER WHAT YOU THINK.

Old guideline sizing was 1 sq in per gallon. So 100 g = 100 sq in.
Old guideline wattage was 0.5 watts per gallon for minimum, 1.0 watts/g for high. As time progressed, but before the new guideline, the "minimum" wattage was considered obsolete. The "high" light level was made the new standard recommendation.

Now, remove tank volume from the equation. 1W per 1 sq in of screen, based on dimensional area, bulbs on both sides, total wattage split between the two sides. This is not in dispute.

Notice that in the original recommendations above, which have been posted all over the internet, a single sided screen is twice the size of a double-lit screen of the same filtration capacity. It says nothing about doubling the light - just putting it all on one side. This is what led me to present my view on the comparison of a double sided screen having 2x the growth/surface area, because this is what allows one to mathematically equate the light coverage for a single sided screen and a double sided screen. In the old guideline, what I call the "light density", which is the wattage per square inch of physical growth surface, is equal in the old guideline.

So....again...

If you have a 100 sq in screen with 100W total, split between both sides, you have 50W per side, each side being 100 sq in in surface area. 100W total on 200 sq in surface = 0.5 watt/sq in of surface.
If you have a 200 sq in screen with 100W total, all on one side, you have 100W on a 200 sq in surface or...0.5 watt/sq in of surface.

The new guideline establishes a different single sided screen light level.

NOW:


If all 12 watts are on one side, it is a 1-sided screen. If 6 watts are on each side, it is a 2-sided screen, but the total is still 12 watts for 18 hours a day.

Feeding based guideline says - same as the prior "high" light guidline - 1W per 1 sq in of screen, based on dimensional area, bulbs on both sides, total wattage split between the two sides. This is "6 watts on each side, total still 12 watts" as stated above. Translation: Light Density of a double-sided 1 cube/day screen is 12W on 24 sq in of growth surface, which equals 0.5 watt/sq in of surface. Exactly the same as it was before.

CHANGE:


If all 12 watts are on one side, it is a 1-sided screen.

It is then followed by a guideline that explains that


1 frozen cube per day (2-sided screen), or
1/2 frozen cube per day (1-sided screen), or...

Which is just a different way of saying that a single sided screen needs to be 2x as large - only now, it just says that a single sided screen of the same dimensional size has only half the capacity of a screen lit on both sides. The difference is the "light density". The growth area of the 1/2 cube/day single-sided screen is 12W on 12 sq in. This equals 1.0 watt/sq in of surface.

Again, this is just fine if this is indeed what is required to equate a single-sided screen to a double-sided screen. But it is different than it was before.

Also, the "high-light" or "high intensity" double-sided screen guideline mandates that one provide 2x the total wattage per dimensional screen area. This means for a 1 cube/day, double-sided, high intensity scrubber, one would have 24W on 24 sq in of growth surface, or 1.0 watt/sq in of surface.

This would then, logically, lead one to conclude that there are only one of 2 options available if one were operating a single sided screen:

1) a High Intensity single sided scrubber requires 2x the light, which would mean a 1/2 cube/day single sided screen (12 sq in of growth surface) would need 24W of light, making it 2.0 watt/sq in of surface, double that of a double-sided screen, or

2) a single sided screen is already a High Intensity screen, and you cannot increase the light wattage further in order to reduce the daily "on" time.

[Garf]

I was under the impression (from 12 months ago) that a double sided screen needed 0.5watt cfl per sq inch run for 18 hours. This is how I did mine and worked a treat. Or the high light option was 1watt cfl sq inch run for 9 hours. So it does seem to have changed somewhere along the line.

Edit- wattages are based on power each side of the screen.

[acorral]

Andres, I am not trying to state that the current guideline is wrong. I am just trying to make the point that it is a change from the previous guideline. How can I be the only one that sees this?



Agree Floyd... I'm not trying to state or deny this as a change (as I'm fairly new on the history behind this conversation)... I'm just trying to avoid this discussion from generating confusion in the general public that reads it...

[Floyd R Turbo]

Garf, it depends on your perspective. Remember, my math above is based on considering the surface area of each side, not the dimensional area, for purposes of illustration. The normal way of calculating wattage required is to use dimensional area, which works perfect for double-sided screens, but becomes harder to explain when dealing with a single sided screen.

0.5 W CFL/sq in for 18 hours, if you consider each side of the screen as an area measurement instead of the LxW dimensional measurement.

The 0.5 W/sq in (which was also watts/gallon, in the old guideline, since screen size was equal to gallons) was the "minimum" requirement, and was based on LxW measurement (dimensional)
1.0 W/sq in was then considered "high" back then.

So on the old guideline, a 100g tank needed a 100g screen with 100W total light - 50W per side - for the "high" light requirement. This was eventually adopted as the standard.

Then, the 'high wattage' or 'high intensity' technique was introduced, a little before the feeding-based screen sizing guideline - it is summarized in the following thread:

http://algaescrubber.net/forums/showthread.php?1958-Updated-sizing-guideline-for-scrubbers


High-wattage technique: Double the wattage, and cut the hours in half (to 9 per day). This will get brown screens to grow green much faster. Thus the example above would be 12 watts on each side, for a total of 24 watts, but for only 9 hours per day. If growth starts to turn YELLOW, then increase the flow, or add iron, or reduce the number of hours. And since the bulbs are operating for 9 hours instead of 18, they will last 6 months instead of 3 months.

As this indicates above, the High Wattage technique for a 1 cube/day double-sided screen is 12W per side, 24W total. This equates again to 1.0 watt per sq in of surface (24W and 12 sq in on each side for a total of 24 sq in of surface). But using the dimensional measurements, which is just 12 sq in, then 24W is 2.0 watts per sq in, dimensionally.

I still recommend considering only dimensional area when sizing screens, because 1) it is easier to explain, and 2) you should really only make double-sided screens anyways, IMO.

[Floyd R Turbo]

Agree Floyd... I'm not trying to state or deny this as a change (as I'm fairly new on the history behind this conversation)... I'm just trying to avoid this discussion from generating confusion in the general public that reads it...

I'm with ya. I'm saying that the fact that there is a difference is actually going to be the point of confusion to the general public. Anyone looking at the old guidelines and building a single sided screen would probably be surprised and confused if someone jumped on their build thread and told them they needed to double the light. In fact, before this, I would have told someone who made such a suggestion that they were wrong, when in fact they were making the suggestion based on a new recommendation, which I did not see nor previously question or make a point of analyzing.

[kotlec]

http://algaescrubber.net/forums/attachment.php?attachmentid=4149&d=1365003234

Need to edit picture and put actual watts required for 1 sq inch. One can then chose whatever type he has and multiply by size of screen.
No confusion regarding linear with whatever... (i hope)

I can make same drawing for leds separately if it is at any usefulness at all.

[Floyd R Turbo]

Double sided would be X=0.5W for normal recommendation, X=1.0W for High-Wattage or High-Intensity recommendation.

Single sided would be Y=1.0W. Unclear on whether or not there is a High-Wattage recommendation. I would opt to say that there is not - it is already High-Wattage/Intensity, the logic being that it must be so due to the known limitations of a single sided screen.

[kotlec]

http://algaescrubber.net/forums/attachment.php?attachmentid=4150&d=1365006519

[Floyd R Turbo]

:)

[SantaMonica]

Vertical, lit from only one side: 24 square inches of screen material per cube of food per day, 12 watts of light on one side.

That's not my guideline, so I don't know where it came from. I would not say to double the area without doubling the watts.


1/2 cube feeding on a single sided screen of 12 sq. in. [3 X 4] requires 12 watts of light

Correct.


So what would 1 cube of feeding on a single sided screen require?

12 sq in [3 X 4] with 6 watts on each side.


Here is the guideline again:


3 X 4 inches = 12 square inches of screen with a total of 12 watts. If all 12 watts are on one side, it is a 1-sided screen. If 6 watts are on each side, it is a 2-sided screen, but the total is still 12 watts. This screen size and wattage should be able to handle the following amounts of daily feeding:

1 frozen cube per day (2-sided screen), or
1/2 frozen cube per day (1-sided screen)

[Floyd R Turbo]

Vertical, lit from only one side: 24 square inches of screen material per cube of food per day, 12 watts of light on one side.
That's not my guideline, so I don't know where it came from. I would not say to double the area without doubling the watts.

This is a quote from my write-up of the "Algae Scrubber Basics", which I posted on multiple sites. It shows that this is how I understood the guidelines to be. I was pointing out that what logically made sense to me at the time was a continuation of the old guidelines, with tank volume removed and feeding level used instead, with nothing else changing. This illustrates the fact that there was indeed a change.




1/2 cube feeding on a single sided screen of 12 sq. in. [3 X 4] requires 12 watts of light

Correct.

This is the change.




So what would 1 cube of feeding on a single sided screen require?

12 sq in [3 X 4] with 6 watts on each side.

Your answer applies to a double-sided 1 cube/day screen.

The correct answer is (according to the new guideline) 24 sq in (4x6) with 24W of light on one side for a 1 cube/day single-sided screen.

[Floyd R Turbo]

I would not say to double the area without doubling the watts.

This is precisely what you used to recommend. I don't understand how you cannot see this and at least acknowledge it.

Old guideline:


Scrubber Quick Guideline:

0.5 actual (not equivalent) fluorescent watts per gallon MINIMUM [0.13 watts per liter].
1.0 actual (not equivalent) fluorescent watts per gallon for HIGH filtering [0.26 watts per liter].
1.0 square inches of screen per gallon, with bulbs on BOTH sides (10 x 10 = 100 square inches = 100 gal)
[1.64 square cm per liter]
2.0 square inches of screen per gallon, if vertical but lit on just ONE side. [3.28 square cm per liter]
4.0 square inches of screen per gallon, if HORIZONTAL [6.56 square cm per liter].
1.5 actual (not equivalent) fluorescent watts per gallon if HORIZONTAL [0.4 watts per liter].
18 hours of lights ON, and 6 hours of lights OFF, each day.
Flow is 24 hours, and is at least 35 gph per inch of width of screen, EVEN IF one sided [60 lph per cm].
Very rough screen made of roughed-up-like-a-cactus plastic canvas.
Clean algae off of screen every SEVEN (7) days NO MATTER WHAT YOU THINK.

Neglecting "gallons" in the old guideline, the screens were proportional.

- A single sided screen was 2x as large as a double sided screen

- A horizontal screen was 2x as large as a single sided vertical screen, and therefore 4x as large as a double-sided vertical screen

- Nothing is ever said about doubling the total wattage on a single sided screen

- Notice that you indeed did recommend increasing wattage on a horizontal screen by a factor of 1.5. But that increase on a watts per area basis actually still leaves the light level on a horizontal screen less that a single-sided vertical screen, even under the old guideline. Example: a "100 gallon" horizontal screen would be 400 sq in with 150W on it. That's 0.375 W/sq in of surface area. Compare that to a vertical single-sided screen of 200 sq in with 100W on it, which is 0.5 w/sq in of surface area.

This is my point. I never saw a recommendation to double total wattage on a single sided screen. I would have noticed that and passed that recommendation on whenever I saw a single sided screen build.

Doubling total wattage would not have made sense under the guise of the old guidelines as the old guidelines didn't even recommend doubling the wattage for a horizontal screen. With the logic you are using, you would have recommended that a horizontal screen have 4x the total wattage because you quadrupled the area. But that was most obviously not the case.

[SantaMonica]

Not talking about horizontal. Vertical only.


The correct answer is (according to the new guideline) 24 sq in (4x6) with 24W of light on one side for a 1 cube/day single-sided screen.

Correct.

The point is, a 1-sided screen should have at least 1w per square [L X W] for 1/2 cube, whereas a 2-sided screen can handle 1 cube with the same watts because of the roots being lit from both sides. Total watts are equal, but 2-sided is stronger.

[Floyd R Turbo]

I was just using the old sizing guidelines, both vertical types as well as horizontal, as an example to point out how the guideline has indeed changed.

So do you at least agree that there is a difference between the old and new guideline with respect to the total wattage of light required for a single sided screen?

I can't see how you cannot.

[rleahaines]

What happens if you have MORE than the recommended wattage on a screen and MORE than the recommended hours?

Example. A 6" X 4" screen or 24 Sq. inches of surface area - one sided. This is for 1 cube per day

The total wattage should be 24 watts or so with normal light [from a CFL] or about 12 watts using LED's. and run for 18 hours.

The double wattage idea for faster growth would be to up the wattage to 48 watts for 9 hours. Or with LED's 24 watts for 9 hours.


To get even better growth and to overcome hair algae in a DT would using even more wattage and hours actually help here?

Example - 24 Watts LED [Red] and 18 hours? for 1 cube daily feeding.

[Floyd R Turbo]

I was looking for one comment and realized that a few posts that preceded this conversation on the other thread did not get moved over. Here they are


With dual one sided screens you require 2x light power compared to one double sided screen of the same size

I guess the way to go whenever possible is double sided...


That's not quite right. if you have 2 one-sided screens, that is the equivalent of one single sided screen of the same dimension. Meaning if you had 2 screens that were each 4x6 and lit on one side, that would be equal to one 4x6 screen lit on both sides (same total wattage in both cases)

Double sided is better because the light on both sides keeps the roots alive longer, as shading is not as much of a factor.


My point is... Speaking cube-wise you need 2x watts per cube on single sided vs double sided

One 3x4 screen requires 12 watts cfl, if its 2 sided those 12 watts are giving you 1 cube/day export capacity

Two 3x4 screens require 24 watts and if they are single sided you get a total capacity of 1 cube/day with twice the power


CDM had it correct a few posts ago.

There really is not two sides to a 2-sided screen; the screen is open and translucent, and each "side" get light from both sides. This is what keeps the roots alive longer. If the screen were not open and/or opaque, it would be two 1-sided screens.

So yes, 1-sided requires twice the light intensity to keep the roots alive. Always has.


I do not recall ever seeing even you give any advice to someone with a single sided screen to increase the light to double coverage. Even your original guideline says nothing about increasing the total amount of light on a single sided screen, is just says 0.5w/sq in for normal and 1.0W/sq in for high - that was before the change to feeding based sizing, but after the suggestion to double the light if you are getting black growth (which eventually developed into a general "2x the light, 1/2 the time" guideline).

I agree that light passes through from each side, and a two-sided screen is not really directly comparable to 1 single-sided back-to-back screens. But it is a pretty close comparison, and logically within reason to describe it as such for matters of apples-to-apples comparison and/or explanation.

I totally disagree that it "always has" been the case that 2x the intensity is required to keep the roots alive, as a generally recommended guideline - because this definitely was not the case. I can find examples all over the place, in the "mega" threads, where you simply recommend doubling the screen size and putting all the light on one side. Never to I recall seeing a recommendation to also double the total amount of light.

Again, I don't disagree with the current recommendation. But it indeed was a change.

Also not addressed specifically is how one would then achieve a "high light" single sided screen. Double the light again? Chances are, this would result in a photo-inhibited screen.

I wanted to expand on my reasoning with respect to this comment:


There really is not two sides to a 2-sided screen; the screen is open and translucent, and each "side" get light from both sides. This is what keeps the roots alive longer. If the screen were not open and/or opaque, it would be two 1-sided screens.

So yes, 1-sided requires twice the light intensity to keep the roots alive. Always has.

While I agree with this for the most part, I still think that considering each side of a double-sided screen as begin separate in terms of comparison for physical area and required wattage is a valid approach. The difference is how long it takes to get to the point of shading, which determines how long the root stay alive. The longer the roots stay alive, the longer the algae will go before the lower layers start dying and releasing nutrients back into the water. Theoretically, at some point in the growth cycle, if you let this go on long enough, the screen will release as much bound-up nutrients as the new growth is absorbing. It does not take as long to get to this point on a single-sided screen as it does with a double-sided screen. The problem is that there is little to no information to prove at what point this actually starts happening for any type of setup, so this is all complete conjecture. As with many processes like this in our hobby, anecdotal evidence is all we have to go by. That and Adey's work on sizing requirements, which is not that different from the old horizontal guideline (sq in based on volume).

Regarding keeping the roots alive and the increase in efficiency, I also agree with this. This has always been the downfall of a single-sided screen. So increasing the intensity of light on a single sided screen is the proper course of action. But it has not "always" been that way.

We all know that these guidelines are not really set in granite. They are meant to get you approximately where you need to be, because every system is different and may have different results. I have one customer who is running an L2 on a 200+ gallon system that is feed 10 cubes/day and he has no algae in the tank (he also runs skimmer, carbon, and filter socks). So there is a liberal amount of wiggle room, and also very much a lot to learn about capacity and intensity factors, and where they play in.

So if higher intensity light penetrates deeper, then at what point does shading from growth just inhibit light transmission no matter what? At what point is there too much light, by duration and/or intensity, resulting in growth inhibition? I'm starting to see things that point to the answers to these questions. The fact that the HOG.5 UAS went from 2 LEDs to one shows me that you (SM) saw this as well. There is definitely an upper limit to intensity. I think it was safe to double the wattage on a single sided screen. I do not think it is safe to recommend doubling it again for a high-intensity single sided screen, at the very least not from the start. Bare screens, in my experience, will start to grow very, very slowly under extremely intense lighting conditions, especially in saltwater, and especially on a UAS in saltwater. Once growth has 'kicked in', then you can start increasing intensity and duration. This is the caveat that has been missing; the screen curing/maturing conditions (may) need to be different from the long-term conditions.

I am thinking that one of the driving factors behind this change is that the UAS scrubbers are generally difficult to build in such a way that they are lit from both sides, so a single-sided solution needed to be made more robust, and the answer was in changing the guideline to match the requirements of the UAS in order to make it work right. Don't get me wrong, it was the right move and it makes sense, but why sneak it in there? Not even a mention of it - just "here's the new guideline" - not "by the way, single sided screen are now required to have 2x the light as I recommended before". To me, being very detail oriented, would have been an important thing to note.

[Floyd R Turbo]

What happens if you have MORE than the recommended wattage on a screen and MORE than the recommended hours?

Example. A 6" X 4" screen or 24 Sq. inches of surface area - one sided. This is for 1 cube per day

The total wattage should be 24 watts or so with normal light [from a CFL] or about 12 watts using LED's. and run for 18 hours.

The double wattage idea for faster growth would be to up the wattage to 48 watts for 9 hours. Or with LED's 24 watts for 9 hours.


To get even better growth and to overcome hair algae in a DT would using even more wattage and hours actually help here?

Example - 24 Watts LED [Red] and 18 hours? for 1 cube daily feeding.

rleahaines, as I mentioned in my above post, I don't think you can double the lights on a single sided screen, unless the screen is fully cured, and even then, I think it would photo-inhibit growth.

Regarding LEDs, I prefer to start that conversation in terms of coverage instead of wattage. Because Deep Red LEDs don't run at 3W - more like 1.5. "3W" is still used for marketing, because efficiency went up so power usage went down for the same output. 2.0V * 700mA = 1.4W. But we all still call them 3W.

Minimum: on each side, one 3W 660nm Deep Red for each 4x4 section of screen.

This works out to a total amount of 6W per 16 sq in section (dimensional area - LxW), or 0.375 W/sq in.
This would compare to the "normal" level of CFL on a double-sided screen of 1.0 W/sq in (such as a 16 sq in screen with 8W of CFL on each side, for a total of 16W)
Notice that this level is less than half (3/8) of the wattage required if using CFL at the normal level. **IF** you consider them to be "3 watts". They are actually 1/2 of that, but the bandwidth is that much more efficient.


Maximum: on each side, one 3W 660nm Deep Red for each 2x2 section of screen.

This works out to a total amount of 6W per 4 sq in section (dimensional area - LxW), or 1.5 W/sq in. A 16 sq in screen would need 4 3W LEDs on each side, so a total of 24W
The "high" level of CFL on a double-sided screen is 2.0 W/sq in (such as a 16 sq in screen with 16W of CFL on each side, for a total of 32W)
But, the LEDs are actually 4x the concentration. This is the difference. What I find is that at this level of intensity, you need diffusers if the LED array is close enough to the screen, at least until the screen is cured.
Notice that this level is about that 3/4 of the wattage required if using CFL at the normal level. Again, really only 1/2 of the actual power used, which means as far as your actually wattage used, it's still less than half (3/8) of CFL


Supplement with Royal Blues running at 1/2 power (diffused, blocked, wired differently, however you prefer) at a ratio of no more than 1 Royal Blue (half power) for every 3 Reds. These do not count into the calculation.


So I guess if I had to write a guideline, using "3W" LEDs, screen size (LxW) in Sq In x 0.375 W/Sq In / 3 give you the total quantity of LEDs needed (both sides) for minimum light. If the screen is 16 sq in, 16 x 0.375 x 3 = 2 LEDs

For maximum light, screen size (LxW) in Sq In x 1.5 W/Sq In / 3 give you the total quantity of LEDs needed (both sides) for minimum light. If the screen is 16 sq in, 16 x 1.5 x 3 = 8 LEDs

[rleahaines]

Bud,

I currently am trying out an array of 6 red LED's - for a screen that is 6" X 4 " that also has 2 blue LED's in the array.

I am using a diffuser as well. The screen is mature. I have used it for 3 months at this point.

It is on a UAS as well, single sided as I said.



I was wondering why I was not getting the growth I should in the center of the screen and real good growth around the edges.

The screen works very well to keep Nitrates at 0 and phosphates low - less than .2. [this could be better, but I don't have anything in the take except softies and some fish, snails and crabs.]

I really want to get this going very strong so it overcomes the hair algae in the DT.

The scrubber runs 18 hours/day. The DT lights are now on an 8 hour cycle.

I am looking at the possiblity of going back to a waterfall scrubber instead of a UAS to see if that gives me more growth and works better.

Total system is about 42 Gal. counting the fuge.

[SantaMonica]

Well I wish I had enough energy to type as much, but I can barely keep up with reading. Anyways, I don't recall changing anything, so it's probably just a mishap.

As for increased filtering, the more watts until you get bright yellow growth is usually what you want.

[Floyd R Turbo]

Bud,

I currently am trying out an array of 6 red LED's - for a screen that is 6" X 4 " that also has 2 blue LED's in the array.

I am using a diffuser as well. The screen is mature. I have used it for 3 months at this point.

It is on a UAS as well, single sided as I said.



I was wondering why I was not getting the growth I should in the center of the screen and real good growth around the edges.

The screen works very well to keep Nitrates at 0 and phosphates low - less than .2. [this could be better, but I don't have anything in the take except softies and some fish, snails and crabs.]

I really want to get this going very strong so it overcomes the hair algae in the DT.

The scrubber runs 18 hours/day. The DT lights are now on an 8 hour cycle.

I am looking at the possiblity of going back to a waterfall scrubber instead of a UAS to see if that gives me more growth and works better.

Total system is about 42 Gal. counting the fuge.

Well I see a few things.

This is your scrubber currently, right?

http://algaescrubber.net/forums/showthread.php?2248-UAS-air-flow-vs-Water-Flow

Are the blues the Royal Blues, or are they the True Violets?

My UAS which was 2-sided took what seemed like forever to get growth. Might have been many factors - did a lot of tweaking. Even then, it still did a poor job of filtering, my guess is because of turnover rate of the water. IMO bubbles do a great job of causing the random action and exchange, but strong laminar flow delivers more nutrients faster. But, I haven't tried very many UAS configurations, so my experience is limited.

Anyways, I think your lights may be on too long. Knock them back to 9 hours/day for a start and let me know if those are blues or violets.

[rleahaines]

the blue lights are the royal blue

reds are the deep red - same as what you are using in your builds.

Not getting any yellowing - to answer SM.

As I said before, the UAS is working fairly well but it is not giving me the kind of growth to overcome the hair algae in the DT.

I don't get the thick mat that I see on some of the posts here about waterfall scrubbers.

[Floyd R Turbo]

Are the blues running at the same power as the reds, 700mA?

[rleahaines]

Right now they are. I am using a diffuser at the present and the screen is fairly mature. Not really getting "burning" just not as much growth as I would like.

[Floyd R Turbo]

I have 2 suggestions. First, I would place a small square of black electrical tape over the diffuser, lined up in front of each blue LED. Just a square, same length as the width of the tape. See if this makes a difference. The blues may still be overpowering the rest of the screen.

Leave everything else alone and give that a week or two and see if you notice a change.

Since you're not burning the screen, I would not reduce hours.

However, you may benefit from removing the diffusers if your screen is mature. The issue is the blues - you have to knock down the intensity. Have you seen my pics of how I wire the blues in parallel within the series string? This really helps, because blues have more radiant power than the reds, so you don't need them at as high of a drive current. Wire them so that the run at 1/2 current and you can remove the diffusers completely, which will up the intensity and may allow you to reduce the hours and get the same growth. Meaning that as you increase load, you can increase the hours again to compensate

[celtic_fox]

... Have you seen my pics of how I wire the blues in parallel within the series string? This really helps, because blues have more radiant power than the reds, so you don't need them at as high of a drive current. Wire them so that the run at 1/2 current and you can remove the diffusers completely, which will up the intensity and may allow you to reduce the hours and get the same growth. ...

Hi Floyd!

Would you mind linking or posting those pictures?

Thanks!

[Floyd R Turbo]

L4 fixture

http://i611.photobucket.com/albums/tt191/FloydRTurbo/00%20Algae%20Scrubbers/DIY%20LED/IMG_0294.jpg

one side

http://i611.photobucket.com/albums/tt191/FloydRTurbo/00%20Algae%20Scrubbers/DIY%20LED/IMG_0295.jpg

Closeup of parallel wired blues

http://i611.photobucket.com/albums/tt191/FloydRTurbo/00%20Algae%20Scrubbers/DIY%20LED/IMG_0298.jpg

[celtic_fox]

Ah. I had no idea it was that simple to switch and then switch back again. I thought some sort of splitting and combining devices would be necessary.

Thanks again!

[celtic_fox]

Oops, that brings up another question... Those are all "3w"? (I know, they aren't 3w anymore, but just catagorizing them.) Or are you dropping down to 1w for the blues in parrallel? (I wouldn't assume that's not prossible, or at least not recommended, but electrical engineering is not my strong suit...)

[Floyd R Turbo]

re-read post #45, yes they are all 3W, and blues are supplemental and do not count towards the wattage total for screen sizing purposes. The 2 blues at 1/2 power actually have more output that a single blue at full power, because LEDs get more efficient as you dim them (or less efficient as you drive them harder, however you want to look at it)