Mnemia

Hi,

I've been having a slight problem with BGA in my tank in the last few weeks. It's a very slow-growing variety of BGA, and hasn't been too invasive as of yet. I first noticed very small patches of it on my Rotala and Cabomba leaves. When I did a trimming, I trimmed the few stems that were affected extra short and took out all the visible BGA. I cleaned up all the loose BGA I could see with the siphon.

At the same time, I started adding a bit of extra KNO3 to my dosing just to make sure I was getting plenty (although I've been dosing the same amount in this tank for nearly a year and I've never had BGA before). I was thinking it might be consuming it a little faster because I moved and the tank gets some indirect sunlight in the morning now => fast stem plant growth. I don't have a nitrate kit that I trust at the present time (the one I have is way off now), but I'm dosing a ton (EI method) so I doubt it could be very low. Same water movement I've had for a year being provided by a HOB filter plus an internal CO2 reactor.

I have very little other algae; sometimes I get a little bit of green fuzz on the side of the glass where the sun hits it in the morning. I think the water parameters are pretty good, plenty of CO2, etc; plants are growing like crazy. But this BGA is still being a slight nuisance and showing up in tiny patches on the substrate and stem plants. Anubias and driftwood seem unaffected. Am I going to be forced to do something drastic like a blackout to get rid of it? I really would like to avoid that if possible since the plants are looking so great. And there is no way I'm using antibiotics in there except as a last resort. Any other suggestions on something I can do?

niko

You may want to try syphoning the gravel and trying to get out any floating debries. BGA seems to show up if there are a lot of organics in the gravel.

The other way to fight it is Erytrhomycin (EM) sold as a pet fish medicine. 200 mg per 10 gals kill the BGA in a day. Guaranteed. You do a water change after that and that is it. But if the reason for the BGA appearance is there they will quickly return.

--Nikolay

Mnemia

Well, I seem to have mostly solved this issue. I think the problem was actually temperature fluctuations caused by a malfunctioning heater. It wasn't kicking on at all, and so the temperature was dipping 10 degrees F at night. I replaced it, and once the temperature stabilized, the BGA died back and is almost gone now. I didn't change anything else, although I did do three extra large weekly water changes. Is temperature a known factor in the growth of cyanobacteria?