Cyanobacteria, Dinos, or both?

DragonWrasseFan · Mar 18, 2026

Please help me identify. I do not have a microscope so I cannot post pictures of that. The tank is over a year old, my nitrate bottomed out in the last week or two and I stirred up my sand bed a little too much by moving some things around. Still not completely sure what caused it. It flares up during the peak intensity light times, and does calm down at night, but it doesn’t totally disappear from the rocks. My phosphate is still 0.5 when my nitrate is barely detectable. I ran sockless on this 15 gallon nano for a few months and then decided to put the sock back in because I was tired of having debris constantly floating around in the tank and it started irritating corals. Not long after adding the sock back in my nitrate started dropping really fast even though I changed the sock out every four days. Now I’m dealing with this mess and it doesn’t look like it wants to go away. I am trying my best not to use chemicals like chemical clean because I do not want to kill anything in my tank, and I don’t want to use a Band-Aid. Also, I’m currently using poly lab reef safe medic so now I’m unable to do water changes for the next 20 days. Any help would be greatly appreciated. Thanks

20260318_181028_72C565FD-6E5C-4AFB-B94D-269196668A89.png

20260318_181028_AFAD16D0-F751-4C92-AADE-F641B2ECB8BB.png

mcarroll · Mar 19, 2026

IMO cyano alone isn't THAT bubbly....and the "snot strands" in the second photo don't look red enough to be JUST cyano.

Try the shake test. Get a sample in a container. Shake it to smithereens. Place the container with the sample under your lights (or in the sun, etc) and see if any of it converges back into a mass. Only dino's will do that.

DragonWrasseFan · Mar 19, 2026

mcarroll said:
IMO cyano alone isn't THAT bubbly....and the "snot strands" in the second photo don't look red enough to be JUST cyano.

Try the shake test. Get a sample in a container. Shake it to smithereens. Place the container with the sample under your lights (or in the sun, etc) and see if any of it converges back into a mass. Only dino's will do that.

Thank you! I will do that. Also, I don’t know how much of a difference this makes, but the photo of the stuff on the sand, I paid attention to it last night and it did stay there all night after lights were out.