SPS bleaching when removing GHA

Gonzo Reefing · Sep 22, 2020

at first I thought it was unrelated, but for the third time I have moved GHA via slowly scrubbing rocks and holding a siphon next to the brush. Inevitably some loose GHA churns in the tank but i catch most of the non microscopic portions while the rest get caught in the filter socks.

Why is this causing otherwise colorful corals to bleach? Polyp extension seems unaffected and zoas and LPS also don't seem bothered. Matter of fact, some across dont seem phased but others turn nearly completely white. Now I'm paranoid to continue fighting the battle against GHA.

I have tested nutrients before the cleaning and again about a week after each time and there are no swings. No3 at about 5 ppm, and PO4 at .01-.03.

Any help on how to avoid the corals stressing out while continuing to battle GHA would be appreciated.

C. Eymann · Sep 22, 2020

You sure its hair algea ? if so is it bryopsis or debersia ?

sure its not lyngbya cyanobacteria? (looks very similar to debersia/gha) almost need a microscope to differentiate between the two.

Lyngbya can actually be toxic.

Gonzo Reefing · Sep 22, 2020

Pretty sure it's not bryopsis. I just looked up the cyano you mention and man, it looks just like hair algae on google. Either way, so far it seems I have to let the corals recover before I continue attacking this stuff unless someone knows how I can attack it without adverse effects on corals.

@C. Eymann 2 questions:

Does this kind of cyano root itself? what I have roots to the rocks in crevices and I gotta really get in there with the brush or else I start to see it grow back within a week.

If it could be the cyano, would chemiclean kill this kind of cyano?

I have fluconazole but don't want to dose the tank with crap, and also have an ATS, and fluconazole would also reset my scrubber most likely.