"Scott" wrote in message
...

I have had blue green algae in my aquarium since I first set it up in
November last year. it started as a small patch on the gravel in the front
of my tank and very quickly spread over the plants and gravel forming into
sheets. I removed the sheets and gravel cleaned weekly but it did not stop
spreading and the algae was back in force every three days or so.

Go to a veterinary and get some erythromycin. This reliably kills BGA.
You can find detailed instructions for the treatment regime at
http://www.myfishtank.net/articles/bga.php, (It might be a good
idea to print out that sheet and take it with you to the vet, so he can
see what you want to do.) I've used these instructions in the past
myself with great success.

One additional tip: if you use erythromycin, don't tip it into the
tank directly, but put it into a small bottle of water first and
shake it up vigorously. If you don't do this, quite a bit of the
antibiotic just ends up sitting in lumps on the substrate.

Cheers,

Michi.