Why is my tank suddenly filling up with algae within two weeks of cleaning?

by Sandy Hoover

I thoroughly cleaned my acquarium six weeks ago emptying all water, cleaning the tubing, replacing the pads, etc. Then a month ago the gravel was so covered with algae the rocks were green and glass covered. I cleaned it by removing a third of the water, put some algae remover pills in water while I cleaned the pads and replaced the carbon. Now two weeks later it is doing the same thing.

A: When you do a complete tear down of the filter for cleaning you will generally lose your biological filtration. My guess is that you have either or both high nitrate/posphate in your tank. Both will encourage algae growth in the tank. You need to do some testing for these elements especially nitrates. We also highly recommend the Algae Fix over the pills which API stopped making many years ago.