DT, not to hijack your thread, but this is a very interesting topic! My bug treatment resulted in HUGE water changes! Everything, even softies, fish, and coralyn algae are looking better! So, what are we adding back (or taking out) that we couldn't test for? Trace elments, dissolved solids, what? I am going to keep my water change voule up a little from before to see if it keeps things going better.