Hair algae - but what kind?

[ReachTheSky]

Been having a heck of a time with this nightmare stuff. I think it came on board with one of my Zoa frags and it's been growing like crazy.

Tank is roughly 7 gallons and was set up about 6-7 months ago. I do 2-gallon water changes every 2-4 weeks. It has an ATO as well. For both, I use RO/DI water strictly (0 TDS). I also use BRS carbon and GFO. For lighting, I have a single PAR38 LED. Due to this insane outbreak, I only turn it on for a few hours every 2-3 days so the corals don't die. At the present moment, livestock is only a Fire Shrimp and a small CUC composed of Cerith snails. There are a few LPS frags as well.

At any rate, manually removing this stuff proves useless. It grows back very quickly. I raised magnesium up to around 2000 ppm with Tech-M two weeks ago and it seems to have had no effect.

Can anyone give me ideas please?

 

[ReachTheSky]

Aww... no one?

 

[GMay]

Not sure this will help, but I would call it the "bad kind". Have tried to go for a total blackout for 3 to 4 days. Not just lights out but wrap the tank in foil or dark cloth. Most algae will not tolerate that well and you may then get a leg up on it when you go to pull it out. If it is on the rock consider removing and giving a good scrubbing before the blackout.

Your critters will tolerate that period of darkness.

 

[ReachTheSky]

The "bad kind" of algae. :lmao: Thank you for that. I realized it wasn't good by any means when it started to ruthlessly take over. I was fishing here for a name so I can research it and target it directly.

I thought it was Bryopsis because it looks like it. After a common and effective treatment (magnesium overdose via Tech-M) did nothing to slow or stop the outbreak, I concluded that it probably isn't Bryopsis.

Next time I do a water change, I'll consider a total blackout for 2-3 days. It's a small tank so completely covering it up wont be that hard.