Up and running for a few months, need to tweak. Suggestions Please

[wardda]

I'm running a DIY over sump waterfall ATS. The dimensions of the grow area on the screen are about 10"x10". I have it powered by a mag 5 which is pushing out about 35 gph/inch. Lighting is two compact florescent twist lights in your standard aluminum clip reflectors on each side, so 4 bulbs in all. They are running 12 hours a day. Standard 12 on 12 off opposite my display. I seem to have nice dark growth in the area above the direct line of light closer to the outflow from the slit pipe. As you can see in the picture I'm getting growth but it isn't the dark green algae, more of a light to mid brownish/yellow, and I still have a lot of hair algae and cyano in my display and a ton of red fuzzy algae in my frag tank. I have been feeding about a cube a day of high nutrient home made food, but with the level of algae I'm getting in the display and fag tank I don't think the normal cube ratio to screen size makes sense. Overall system volume is about 220 gallons.

This scrubber is replacing a smaller one that was running about 8 months and just couldn't keep up, same design but only one bulb on each side and a 5x10 screen, but it was powered by the same pump, so much higher flow/inch. But the smaller design grew dark green long algae, but it wasn't able to keep the display free of hair algae or cyano or the frag tank free of red fuzzy algae.

So based on the picture of what I'm getting what do you recommend?

3953

[SantaMonica]

Clean all off, go to 18 hours, let grow 14 days.

[Floyd R Turbo]

The usual wisdom would tell me that your screen is overlit and/or under flow. If you had green hair algae before with the same overall quantity of flow and 1/2 the light, that would seem to match that wisdom.

Your Mag5 may or may not be supplying enough flow. With head loss, which can be roughly calculated by vertical head (actual) plus about 24" for the slot pipe (at least, that's what my bench testing has confirmed - 12-24" of "equivalent" head created by the slot pipe with a bare/new screen) then you're looking at probably 36" equivalent loss. This would seem to be consistent with Danner's flow chart on the Mag 5 (http://www.dannermfg.com/Store/images/instructions/ZG120.pdf).

So in summary you have decreased the flow per lineal inch by 50%, and kept the overall light level the same, or even potentially increased it. I would increase the flow. You might also check to make sure your slot pipe is the proper width all along. What I have found is that when you cut the pipe, even if you use a table saw, the pipe naturally pinches closed a little. So as you cut the pipe, initially your cut width is right, then as you go back along the whole slot afterwards, the ends are wider than the middle. It took me a long time to realize this, and it even happens on Schedule 80 pipe, though it's hard to notice. This is why I started cutting my slot pipes with a router and taking 2 passes. Even a 6" slot closes up a bit in the middle. Not much, but I'm a perfectionist.