Cyano or something else?

[indigoze]

So I've rapidly developed this maroon/purple colored gunk all over the rocks in my tank.There were a few spots on the rocks last week but now it's everywhere. It grows very rapidly and and is easy to remove with a blast of water from a baster, which I would think cyano from the other posts I have read but it never grows on the sand, just rocks and in the macro algae as well. Snails eat it but they can't keep up. I have very low phosphate (finally lol) and nitrate, and zero nitrite water wise. Those water parameters have been stable since around the end of December. It is unaffected by flow and is even on the grate of the flowmaker thing I have. There is no stringy or fuzzy growth to it just looks like velvet.

I've read chemiclean causes more trouble in the long run and I don't want to try it unless this is indeed cyano.

 

[Subsea]

Details matter. What is very low, ppm please.

Looks like Cyanobacteria to me. I suggest getting your nitrates above 10ppm and phosphate above 0.03ppm up to .1ppm.

Where did you read that ChemiClean causes long rang trouble? Be careful of that source for information.

I use it when required.

 

[indigoze]

Nitrate is less than or up to 2ppm never goes higher; phosphate doesn't register at all. Totally eliminating the phos eliminated my diatom issues, and if I have to choose between them and the purple velvet I'll take the latter, as it is at least not unattractive just rampant in it's growth.

Regarding the source on the chemiclean several YouTube videos indicating they had dinos after using it, with no other changes to their routines. Also posts on here and on other forums that I read but am not a member of. Reef2reef seemed to be the best one IMO.