I do agree with Larry that water changes are good. However There are some of us (me) who have chosen to slow down on them for several reasons. My biggest reason is, I've discovered dosing! By dosing 2 part I'm able to keep a better handle on my ca/kh levels. So they are always there when my corals need them. As far as trace elements, well I dose those too just not every day. 1x bi-weekly. To be honest, ever since I stopped the weekly 20% water changes my corals (zoa's especially) have flourished. I have a small system, 26g and I do believe that my weekly water changes were shocking everything. To much of a good thing I am now enjoying my tank a lot more It's been like 6-7 weeks since my last wc and my tank's never looked better.