GHA Eradication


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Peachtree City
Hi all, I have read posts going back 15+ years and have not been able to find a solution to work for me with this GHA problem. I have a 36" deep corner tank (deep tank), 125 gallon (130 gallon with sump and minus the rock/substrate). System has been running about 12 months now and corals in the tank for about 5 or 6 weeks. GHA problem started about 3 months ago when I went on vacation and came back to it covering about 25% of the lower 1/3 rockwork. Rock work comes up a good 24" from the substrate. I have read that manually removing GHA regularly is the best way to deal with it and try to find the root cause, which I can not seem to figure out.
Tank parameters:
Phosphate - .01 - .04
Nitrates- under 5
Alkalinity- 8-9dkh
Salinity- 1.025
Temp- 78
Calcium- 450
Magnesium- 1350
Ph- 8.1

I have also read that even though the phosphates and nitrates read low, it could be that the GHA is taking it up quicker than you can get a reading on. Problem with that theory is that after I scrub 90% of it off the rocks the parameters stay exactly the same all the way to the point it starts growing back again within 2 weeks. Parameters never really change, so I dont get it. I have an ovesized protein skimmer, Reefmat 1200, UV and carbon reactor (reactor is only used periodically). Nutrient export does not seem to be a problem.

I feed with a plank feeder freeze dried food 3 times per day the equivalent of about 2 frozen cubes a day. I have 11 fish in the tank all between 2-4" long including a PBT and a Foxface that are doing the job. I also have about 6 Mexican Turbos snails, a dozen small blue leg crabs and mix of about a dozen astrea a trochus snails. I also tried a sea hare as many have had luck but he would never climb the rock to get to the GHA. He mostly climbed the glass or overflow and then hid in the substrate the rest of the time starving himself to death. After a month I gave him back to the LFS.

I have a Neptune sky running AT 30% and 2 Kessil A360s running at 30%. At the top of rock I am at roughly 180 par and sand bed at about 50 par. The lights start at 5% and ramp up 4 hours to 30%, stays there for 5 hours and ramps down for 3 hours until off. The GHA continues to come back from the base rock to about 1/3 the way up, which is strange to me as the GHA needs light and yet it is only growing in the lowest lit areas?

I have tried Reef RX and read that it could take 4-5 weeks so I turned off the skimmer for 3 days and turned off the UV and carbon reactor for the entire 5 weeks and did no water changes. Surprisingly the parameters stayed pretty consistent through it all, but the GHA continued to grow through the entire process.

It is EXTREMELY difficult to manually remove the GHA as it is so far down in the tank but after about 2 hours a week with all sorts of extension brushes and my arms at least elbow deep, I can clean over 90% of it but what a pain and not making this "hobby" very enjoyable or rewarding. At this point its more like a job, and im retired!

I have not set up a fuge which the theory is that Chaeto will take up the nutrients and outcompete the GHA in the display. I can set it up but my sump does not have an ideal set up for it and I am not sure it will really take care of the problem seeing that nutrients do not seem to be the problem.

So with all that said, other than setting up a fuge does anyone have any other suggestions?


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The turbos were always what took care of it for me. Are they touching it at all?
They generally stay on the glass and do not wander up and down the 2 feet of rock, even when in place them there. They are back on the glass next morning.
That stinks, man. I'm sorry. Both times I had awful hair algae, I got a turbo and he decimated it immediately.

Maybe try a long spine urchin? I've never had one, but they have a great reputation for liking hair algae.

And you're sure it's GHA and not bryopsis?
Yes, it’s GHA. I am going to try Vibrant per Steve’s recommendation above. I read a bit about the Algeafix being the same active ingredients as Vibrant but Vibrant also comes in 3 types, freshwater, saltwater aquarium and reef aquarium. I read a post from a guy who lost some corals as he inadvertenly bought the saltwater version not knowing there was another version specifically for reef. That said, I don’t know which “version” of Vibrant is the same as Algeafix so I am going to use Vibrant for reef. It is almost 3x more expensive but it is not worth the chance of losing thousands in corals over $30 in savings.
I will post once I see how this shakes out over the next couple of months as it seems to be a slow process. Thanks for all the help guys!
For what it's worth, there's an active conversation going on over at R2R where a guy is having a problem very similar to yours. Might be something helpful for you in there — or maybe not. Figured it was worth mentioning, though.

I recently finished a course of reef flux, or fluconazole. It worked great to get rid of bryopsis and Gha over the period of about three weeks. And I had no I'll effects.
I found this to be a great way to start over. You will still need a good clean up crew (I like trochus snails) to control what grows back. But I find it easier to control grow back, then have the cuc control what is already over grown.
I would second reef flux as well. A little bit expensive, but has no adverse impact on my chaeto nor on my corals. You have to dose double, or even tripple the dosage.
During the treatment, you will find GHA starting to turn white and you can easily remove them using a toothbrush. I would change my filter floss daily to remove those dead algae from the water column.
After treatment, you can do a small weekly dose of reef flux to keep GHA at bay.