What are you lighting it with? How many hours are you lighting it? Do you have algae in your display? If so kill your display lights for a few days and light the ATS 24/7. If you don't have algae in your display you may.just have very low nutrients.
It was lit with a ufo light from Amazon. I'm doing a full sump refresh and going to build a waterfall scrubber. Just need to get dimensions and start cutting. With a 9 month old this might be a long process.
Algae in the tank has been steadily increasing, I need to get back on track
In the mean time just rough up your mesh and stick it any where with decent flow in your sump. I am not fimiler with ufo lights. The red and blue LED grow lights really work amazingly well for dirt cheap.
I am still running it. Not much to tweet excep the light schedule. I do need to clean it pretty badly. I have three sheets of the fabric in my overflow. I usually clean 2 and then the last one a week later.
I am still running my scrubber in my overflow. I cleaned one of the 3 mesh sheets tonight. Just to give you an idea how well my scrubber works, this is what came off of one of my three sheets of mesh. The knife is 8" long for reference.