Good morning gentle reefers.
As few of you probably know, I've been battle GHA for a couple of weeks. I'm happy to report it has been defeated, allow me to tell you about it.
The cause of the was a couple things. Nutrient export, of course, was one. Even more than that I, like many other newcomers, rushed my cycle and added a bio load as soon as I believed the tank could support it. The tank was "cycled", and could support my livestock, it had plenty of nitrifying bacteria to process the added ammonia and nitrites. What the tank did not have was the bacteria needed to take the nitrates to nitrogen, I added a bio load as soon as this bacteria started growing and didn't give it time to get a foothold.
So, small patches of GHA started popping up, electric green and not at all bad looking, almost like tiny lawns of grass all over my rock. I took the stance that it was part of "the uglies" and it too would pass.
It did not take long at all to completely overrun my tank. No longer tiny cute lawns, but ugly green everywhere. Quite hard to look at. So the battle began.
I ordered some GFO from my favorite vendor and began a 4 day blackout. I was able to add the GFO on day 2. There was still some green after lights came back on, but I suspect it was already too far gone to return. After 4 days on a 4 hour photoperiod, 2 @ 20% and 2 @ 40%, I wasn't sure that it was all dead so I blacked out for another 3 days. I'm slowly ramping my photoperiod and light back up to 11 hour and 85%, and I am excited with the results. And ecstatic that manual removal or dipping all my rocks in peroxide wasn't necessary!
I read a lot of people getting frustrated while fighting this, but the key is understanding the cause.
Have a good day everyone!