Horizontal scrubber ???

[gilly]

I am in the processes of setting up a horizontal scrubber. It is going to have a screen size 13" x 4.5" (58.5sq"). Have I worked this out right, I have it that it will need 87W of light so say two 40W bulbs 2700K, and that it should handle a little bit more than the example below. Could someone please confirm my calculation so I don't waste money on the wrong bulbs. Thank you very much, James.


New Scrubber Sizing Guideline (Sept 2011)

Scrubbers will now be sized according to feeding. Nutrients "in" (feeding) must equal nutrients "out" (scrubber growth), no matter how many gallons you have. So...

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)

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.

HORIZONTAL screens: Multiply the screen size by 4, and the wattage by 1.5

Flow is 24 hours, and is at least 35 gph per inch of width of screen [60 lph per cm], EVEN IF one sided or horizontal.

Very rough screen made of roughed-up-like-a-cactus plastic canvas.

Clean algae off of screen every 7 to 14 days, so that you can see the white screen material.

[SantaMonica]

Yes that would be a minimum wattage.

Important for horizontal, is to tilt it as much as possible to increase flow.

[gilly]

Thanks for the quick response. Regards flow, the screen is just short of 12cm wide so multiply by 60 tells me I need at least 720lph is this correct?

[SantaMonica]

More. Horizontals needs as much as possible to make it over the islands.

[gilly]

OK, thanks. What would you suggest as a starting point. 1000lph?

[SantaMonica]

Try for 100 lph per cm of width.

[gilly]

Thanks for that, will do.

[mattberrytr]

Any update re this? Have you got it set up yet?

[Creekview]

I've been running a horizontal flow scrubber for about 4 months now. It services two systems, a 33 and a 55 tied together in a continuous loop. An 800gph pond pump provides flow through the loop. My screen is 5x24. It is illuminated with a 10w red/blue LED and a 10w blue/white LED. It does just what it's supposed to do, keep the water nice for the critters. Its my 4th iteration of a DIY scrubber, and is by far the most effective I've tried. It's also a very productive pod farm. Couldn't be happier.

[mattberrytr]

Sounds good, how much do you feed per day?

[Creekview]

2 cubes and 2 pinches. I also have several different macroalgae in my display tank. I supplement with iron.

The blue/white LED is an experiment that has me building a "tunable" LED array that covers all of the peak wavelengths of marine algae. There are 5 individually adjustable arrays of three 3w LEDs, 440 & 460nm blues, 6500k white, and 620 & 660nm reds. I want to see how each wavelength impacts the algae variety and growth. I'll post some pics this weekend.