No change.
No change.
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
What do you mean - I asked 2 questionsOriginally Posted by SantaMonica
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?
Yes. It's all about keeping the roots alive.Making it double sided doubles energy efficiency in terms of cubes/day per watt
Lets get this straight. over a year ago, I posted this update to the Algae Scrubber Basics.
Are you telling me now that this was incorrect?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.
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.
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).
Previous guideline:
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.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.
Now:
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.
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?!?
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
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