-
Catherine
Hello forum members, I am reaching out for your help to identify what this is and for advice on how to deal with it. The aquarium is 2 years old, and I previously had issues with cyanobacteria, which I successfully battled twice. However, this started about six months ago when all the rodactis began to split into smaller ones and eventually died off. During this time, the aquarium began to overgrow as shown in the photo, and several more corals died. Over the course of a month, I managed to stabilize things, and the corals stopped dying, but I can't seem to get rid of this nuisance. During water changes, I collect as much of this algae as possible, but within a week, it grows back to the same state, spreading everywhere - on the rocks, sand, glass, and on the rocks closer to the light with bubbles, while there are no bubbles on the sand. The aquarium is 140 liters with a 60-liter sump. Salifert tests show: NO3 - 0, PO4 - 0, TDS - 2, Ca - 400, Alk - 7 (currently raising), pH - unknown. I'm curious why NO3 is 0 and PO4 is 0? I found information on websites that this kind of picture usually indicates dinoflagellates, but since I previously dealt with cyanobacteria, I also suspect it might be Calothrix?