Green water

[Richer]

A small ammonia/nutrient spike probably caused the green water bloom. All levels are inline, because the algae in the water is absorbing all the nutrients in the water column. Water changes will not fix this problem, as any leftover algae in the water will multiply very quickly. A black out method will work to fix the problem.

Increase the surface aggitation of the tank, do a 50% water change, clean out the mechanical filters in the tank, and/or add more mechanical filters (ie. those powerhead quickfilters). Shut off your lights. Cover the tank with heavy blankets/black garbage bags, and make absolute sure that no light gets into the tank. Leave for 2-3 days. During this time, do not feed your fish. If your friend has plants, don't worry about them. Healthy plants can do without light for a 2-3 days, though some plants can get a little "leggy". Afterwards, remove the tank cover, do another 50% water change and reset the tank to its original setup. Afterwards, just make sure the nutrient levels in your friend's tank is good, and the green pea soup shouldn't show up again.

-Rich