Nitrates still high

[rog2961]

Started my scrubber when I setup my tank so since it was cycling this has been running. I originally had two 10x10 screens each lit on one side and realized that was way too much for what I need. I have since knocked it down to one 10x10 screen lit on one side with two bulbs. I feed probably one cube a day. I am currently on week 6 now and have not cleaned the screen yet. I have some growth of bright green algae that I can see is starting to turn slightly yellow. I leave the lights on for about 12-15 hours a day. Should I clean now or continue to let the screen fill in a bit? It's currently a bit spotty on the screen and not fully covered. Nitrates shot up to 80ppm after cycling and has been staying there since then. Have performed one water change after cycling and now that its been a week will perform another.

Its a 155g with 50g sump filled halfway. Total volume is about 170 or so.

[Floyd R Turbo]

Do you have any fish in the tank yet? I think you have several threads about the same tank, might be a good idea to designate one as your thread about your tank, otherwise you only get bits and pieces of the whole picture.

So a 10x10 screen, how much flow across it? How much light?

I think no matter what either of these is, you should be able to grow enough algae to consume the nutrients in the tank that you have, so something seems to be off.

Pics of growth would help, because what might be "some" or "slightly" or "this color" to you might mean something else to another, pictures are more definitive.

Going 6 weeks without cleaning might be ok on start up depending on growth (i.e. none for a long time, then 2 weeks of something) but I would still take it out weekly or every other week to clean the slot pipe to make sure flow is even. By now, you should be at the point where you will want to clean some loose growth off and encourage growth on the base of the screen. The yellow may be blocking, depending on the type of yellow.

[rog2961]

Currently only have 2 clowns in there and added two cleaner shrimp yesterday. Flow is about 35g for every inch, Currently its at (2) 23w Cfls on one side of the 10x10. Will get some pictures tonight when I get home. Would yellowing be due to too much light? I thought light closer to the screen would be better but I am sure there is a point at which it gets too close and will start to be detrimental.

[Floyd R Turbo]

With CFLs it seems that it is a little dependent on the setup, which is why pics help. Generally about 4" away is good for 23W lamps in dome reflectors.

[rog2961]

I think this may be my issue. I thought closer was better but the way its setup currently the reflector slopes away from the screen. So at the top where the reflector is close, the algae is brownish black. Where it is further away the screen has thicker green hair algae. In this case I'm assuming I need to bring them further away from the screen? Will get pics when I get home.

[Floyd R Turbo]

That sounds like the result of uneven coverage. If the reflector/lamp is not pointing directly at the screen, as you described, then you might be getting less intensity at the top, then just the right intensity lower down. Again this is really still in the start-up phase of growth, so there will be a lot of inconsistent patterns. You can mess with it as much as you like to get it "perfect", but once the screen fills in better it really won't matter much. At least that's been my experience

[rog2961]

So in your opinion just leave it until it fills in? I was on the same thinking because I thought once the screen gets something on there, it would just spread as time goes on. My only concern is the yellowing. It's the other way around light intensity is high up top, and then lower towards the bottom of the screen. What gets me though is the majority of the growth is on the bottom where the light is further away.

[Floyd R Turbo]

Hmmm...I think I'll wait for the pics to see what is going on, I've only seen the ones from when you had 2 10x10 screens