Blue green algae problem

You'll want to treat with a broad spectrum antibiotic. This usually kills off the beneficial bacteria as well, so use with caution and plan on re-cycling the tank. Manually remove as much as possible each day to shorten the time needed to treat.

Painter…I would recommend trying a complete blackout 3 days first. If the BGA is really out of control, I have had great success treating with erythromycin, but…use only ½ the recommended dose for about 5 or six days. My reading, research and experience tell me that erythromycin will not kill off your beneficial bacteria. You can buy it at most pet stores in 250-mg. tablets. I used aprox. 15mg/gal per day for 5 days. BGA is gone, poof! Everything else is fine.

Normally a single dose of EM at full strength will eliminate bga though a 2nd dose may be needed. Before you dose manually remove as much of the bga as you can. When the one or two doses have been made, do a vacuum, filter clean and water change and add new carbon back into the filter. The EM kills the bga will will produce ammonia. Taking the above precautions prevents turning one problem into another.

I have found that in a well planted tank the bio bed is minimal as the plants handle that job. Therefore antibiotics have little effect on things.

This is where some controversy begins to creep in. Just like your doctor tells you “complete the full course of antibiotic treatment, do not stop taking it until the entire dose regimen is finished”. Cyano is a bacterial infection of the tank. You need to kill it. Do not let it become a drug resistant strain by only “sort of killing it”. Do you get my drift?