[Lance]

I just read an article by Dr. Dieter Brockman who says:

Quote: "It is the experience of many aquarists that a change of between 10 and 20 per cent of the water per month is optimal for reef aquariums; higher percentages are, in my opinion, counterproductive. For fish-only tanks, the percentage can be significantly higher, up to 50 percent per month. Partial water changes that go beyond this limit for reef aquariums endanger the system's stability and increase algal growth. For any aquarium system, small and frequent partial water changes are also preferable to a single large one per month: Small volume changes are less hard on the chemical parameters of the system. The current approach to my 220-gallon tank is to replace 12 percent (aproximately 25 gallons) per month, divided into four weekly changes of roughly 6 gallons.