Hi Erica, have you checked the phosphate levels in your tank? If so, what are those levels? Make sure you are using RO water for your water changes. It may also be beneficial to leave the lights off in the tank for a couple of days and when you turn the lights back on, shorten the hours while you try to figure out the cause.
I had the same problem. For me it was a phosphate issue. I got some brown …. I forgot the name of it. It looks like carbon only brown and smaller. Anyhow, I put a small amount in a media rack bag and simultaneously had a 48 hour blackout period and that corrected my algae and cynobacteria issues.
I think Chemi-Pure may be the brown stuff Deric used to remove the carbon. It is good stuff! I always add Chemi-Pure ELITE to my carbon in a mesh filter bag and place it in my filter sock.
I have had green hair algee also and I have tried everything now trying GFO and phosphate spung I have cleaned what I can out so will see how this works..
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