Join Date: Mar 2019
Location: Edmonton, AB, Canada
I can only go from personal experience, as there are many views on BGA treatments. In my own tank, I used hydrogen peroxide (3% strength, standard pharmacy bottle), and used a syringe to spot treat the affected areas. Here are the steps I used:
1) Physically remove what you can. Try to avoid losing any BGA debris in the water column, as it will settle elsewhere in your tank and start a problem there.
2) Shut off filtration and any flow inducing devices. Wait 10 minutes to let currents settle.
3) Using a syringe, gently, without making too many waves or currents, spray BGA affected areas with H2O2. It will start to bubble, this is normal.
4) Leave the tank alone for 20 minutes.
5) Start your equipment back up or do another water change. Byproducts are (I believe) oxygen and water. I still wouldn't spray it in a fish's face though...
I didn't bother with a water change, no adverse effects. Should also note that there is an upper limit to how much H2O2 you spot dose with. I've read 1ml/gallon. I have a 75 gal and never used more than 30mls at a time.
That's it. Might have to repeat a couple of times (never more than once a day, I went every other day). It's been a success so far. I know your tank is smaller, so keep the dose low at first. Hope this helps.