We all seem to agree. On smaller systems water changes are all that's needed. Larger systems with high coral loads benefit from water changes and from careful supplementation of calcium, alkalinity, etc. I don't do water changes at the scale everyone else does as I have a lot of filtration and test regularly. Mr_X on the other hand has spectacular results from keeping it simple and just doing regular water exchanges. There are those of us that suspect he is also using dark magic to grow corals, but that's another thread.