Wow guys a lot of responses. So I have found that my fish respond very well to large water changes. Usually gets them in the spawning mood. I haven't seen any problems from the silver dollars as far as their response to a large water change. I don't alter my water in any way so the same water going in has the same pH as the water going in except the temperature does drop about 2 degrees and the nitrates are lower obviously. So it sounds as though it would be better to do several small water changes instead of one or two big ones like I have been doing? If the fish don't show a negative response to the several large water changes would it matter? I am only doing so many water changes because I have been feeding quite a bit so to compensate I have been doing extra water changes.