Help With Scrubber

[24johnson]

I need a little help. I built my scrubber in November of 2011 and not getting much of growth. I am getting a lot of Red Slime algae in my sump and display.
I used the old formula to build it with 1 square inch per gallon of water.

Here are my dimensions and lighting
Tank is 210 mixed reef
Screen is 17 in wide by 12 tall with 600 gal of flow.
on one side I have two 23w cfl and on the other one 43w cfl. (just comparing if one or two lights work better)
lights are on 18 hrs per day.
Not sure how many cubes I feed per day. I feed Rods Food, wich comes in flat sheet. Just break a chunk off and feed.
Nitrates are 5 to 10 ppm and don't have a phosphate test kit (any recommendations on brand)

I know the screen dimensions rules have change to what you feed, but wouldn't the screen thrive until all nitrates and phosphates were depleted?

[SantaMonica]

wouldn't the screen thrive until all nitrates and phosphates were depleted?

No. The reason is that there are not enough nutrients to build the 3D "ladders" that the long green hairs need to reach up and into the flow and light. Thus, they never get surrounded by flow and light, and thus cannot filter strong enough to out-compete and "pull" the algae out of the display. By reducing the screen size, extra nutrients can go into building the "ladders", instead of "widening the base". The ladders will reach out into the flow and light, and filter much more strongly.

The fix is fairly simple: Tape-up part of your slot with plastic packaging tape, so that it's about 10" wide, to match the width of your reflectors. Put a 43w on each side. Make sure the bulbs are less than 3 months old, and are "warm", "soft", 2700K, or 3000K.

[24johnson]

Thank you for the quick reply. Do I also need to adjust the flow from 600 to 350? How can I compare 1 cube of food compared to a flat sheet of food?

Thanks

[SantaMonica]

Yes adjust the flow, although it will probably adjust itself.

Wet the food and see how much fits into an empty cube.