Floyd's questions about wattage

[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 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

[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/show...E-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.