I do 50% on my 20 gallon weekly and 50% on my 10 gallon every 2 weeks. The reason I do the 10 gallon every other week is because it's understocked....until my fish get bigger.
thanks all good info. so it seems that the consensus is pretty much the more the better. Ill have to check my tap water to see where it is, but weve been using it now for a few months and the water quality seems fine, aside from the slight nitrate problem, so its probably pretty close.
as long as your treating the water there should be no problem. many people do 50% daily water changes at time i do 80% water changes. i do weekly 50% water changes weekly.
A number of years ago I had an angelfish farm on Long Island. I had a continuous water change system. New water dripped in at a rate that, for each tank, changed 200% daily. The water level would rise an go out the overflows to a drain.As an added benefit, the rate of change was slow enough that any water differences in the new water would be easily accepted by the fish. Raised a lot of fry this way and I was also able to feed heavily so they grew quickly. IMO it is not possible to give too high a water quality.