Opinions

[flchamp89]

Tanks 63 days old. Had diatoms still maybe do? Had GHA but it's 99 percent gone. I think it's cyno. This past Sunday when I did WC I used toothbrush on the rocks as I have been for last few weeks. I think it may have been cyno and it's clumped back together. Not really slimy. Not really any bubbles. Look to the right of the cerith.

 

[James M]

Could be diatoms or cyano...hard to tell form the pics