Too many water changes?

[Myka]

There is no such thing as too many waterchanges, but there is such a thing as inefficient waterchanges. Your waterchanges are inefficient. On your waterchange tomorrow you are removing part of that 7 gallons you did today, that is not efficient. for example, you would be MUCH better off doing 49 gallons (7 gallons times 7 days) once per week. In this fashion, ALL 49 gallons removed would be "old" water.

Really though, 10-20% per week is usually quite sufficient for most reef tanks (assuming this is a reef because it is in the reef forums), and most of the time little benefit is seen by increasing the amount changed per week.