Need help

[Morelia]

I have a 90G tank that I setup in early March, and up until lately, everything has been running pretty smooth. I went out of town for 5 days, and came back to a tank full of algae of some sort (Bryopsis?) see pics below. As this is my first saltwater tank, I am unsure of the ID of this unwelcome inhabitant. A little about the tank..... I set this up using dry rock and Caribsea Fiji Pink sand. I used Fritz TurboStart 900 to cycle the tank, and began to stock slowly from there. Below are the parameters as of an hour ago:

PH - 8.0
Salinity - 1.025
Ca - 420 (Red Sea)
No3 - 40 (API)
PO4 - 140 (Hanna UL Checker)
Kh - 9.8 (Red Sea)
Mg - 1350 (Red Sea)

I have (2) Jebao SW8 powerheads on opposite ends of the tank, running 50%. I tried to remove the algae with a toothbrush, with no success. I also wrapped the tank for a 4 day blackout period, with no change. I am running the lights for 10 hours, on a slow ramp, max of 30% (SB Reef Lights). Any help would be appreciated to ID this, and a plan of attack. Thanks in advance!!

 

[NoahMMTV]

How old is your tank? I took a 2 week trip to hawaii when my tank was about 3-4 months old, right when the GHA phase started, and since I wasn't there to clean it, the outbreak was accelerated drastically. It took about 2 months to recover from it, and not even fully. Best way to do it? Make sure your tank is crystal clean, then buy a sea hare to clean up all the algae. I assure you if you have some methods of nutrient control (like GFO) and good parameters from regular water changes, the algae wont grow back, and eventually all die out.

 

[Morelia]

The tank was setup in early March. If it is GHA, wouldn't the 4 day blackout have had some impact on it?

 

[NoahMMTV]

The tank was setup in early March. If it is GHA, wouldn't the 4 day blackout have had some impact on it?

they're tough, probably feeding off those nutrients. Blackout can help but wont eliminate.

 

[Morelia]

So is the consensus GHA...? I was suprised that I was unable to scrub off any from the rockwork with a toothbrush, so I thought it may be something else.

Thanks in advance everyone!

 

[KingReef16]

That could be Bryopsis. It looks a lot like mine. I just dosed with fluconazole today. There’s a great thread about it: https://www.reef2reef.com/threads/bryopsis-cure-my-battle-with-bryopsis-using-fluconazole.285096/
Good luck!