[Nrgman]

Well, I wasted my time, because BGA was back, and really furious. In fact, in a matter of days, I had a really nice Amano style coverage on my plants and gravel.
It was at that time that I read about Erythromycin. It is not supposed to hurt fish and plants, and from what I read most of the biological filter remains unharmed. Since I prefer to use human medicine and antibiotics instead of the ready-made medication available in the hobby (a trend which is actually owed to George Reclos and his precious advice), I rushed into a pharmacy asking for the equivalent antibiotic that was based on Erythromycin. It was called Erythrocin, and surprisingly enough, you don’t need a prescription to buy it. It comes in two forms, 500 mg capsules and spring tablets (the ones that melt in water). A box of 12 capsules only costs at about € 3,50. Imagine how many treatments you can do, especially if you keep small tanks .
The dosage that is most commonly used is no less than 2,5 mg per litre. So for my 60 lt tank (actually less if I consider gravel, plants etc.) I needed 60 x 2,5 = 150 mg. Since I like to overdose a little bit (another trend by George Reclos ), I split the 500 mg capsule in 3 parts (166 mg) and decided that this would be one dosage (treatment).
First day

I dissolved a 1/3 of the capsule completely in a small basket containing tank water. When you spill it in the tank, you will notice small white dots swimming around. It is the medicine. Actually, if you can find the spring tablets, it is much better.
I watched (in agony, I must confess) how the fish would react. They did not seem bothered at all (Some of them were actually hunting the white dots as they thought it was food...Silly bettas... when they are young ). No sign of stress or discomfort.
It is important not to have anything that might decrease the effectiveness of the medicine, like a protein skimmer at that stage.
Second Day

Added 1/3 of the capsule. You should notice extra bubbles on the BGA bed, and you might also see pieces of BGA trying to leave the gravel and head to the surface.
Third day

By the end of third day you might see large pieces of BGA slime floating around. Mine was quite full. Record your ammonia and nitrite levels, and perform a 30% water change if they are high. Try to get rid of the slime by other removing it with a net (as I did) or by using an extra mechanical filter.
Fourth day

By the end of the day most of the plants were clean. There were still some bits and pieces around, but the tank looked much better. The fish and plants were unharmed, like nothing was going on, and everything seemed normal. I performed a 50% water change and added 1/3 of the capsule. I again measured ammonia and nitrite levels.
Fifth day

My tank was almost clean now. The important thing after the third day is the measurement of ammonia and nitrite.
Sixth day.
What happened to me:
BGA was completely gone. The results were amazing. I stopped treatment, performed a large 70% water change, and then resumed normal maintenance.