Since I moved this summer my 30 gallon tank has had horrible cyanobacteria problems. I recently added a Seio to one side bringing my number of powerheads to 3. I have two filters and a HOB refugium on the back of the tank, and it has plenty of circulation. I change out about 25% every week and a half to two weeks and use RO water for changes and top off.
This tank has been established for just about a year and took some time to balance out, and when I moved it all went to heck. I have changed the light bulbs, increased water changes, done everything I can think of! My phosphate level when tested was very very low.
This tank is essentially set up as a 30 gallon refugium as it is designed for my mandarinfish. It has probably 50 lbs of LR. I also have a firefish, chocolate chip star, 3 bumblebee gobies and one small hermit. Very low bioload. I feed lightly and have the tank packed with macroalgae (caleurpa and chaetomorpha) and move it into another tank regularly as it grows.
I am stuck and about ready to tear the darn thing down. I siphon off all the cyano every time I do a water change and in about two days its back. The tank gets a little bit of late afternoon sun for a few minutes but other than that only has a 48" shoplight for light. Its on for about 10 hours a day.
So help, anyone, with any suggestions. This tank just looks awful and I really love it and dont want to take it down!
Here is a pic I took the other night after a big water change: