This is my hypothetical Jeff...the corals were only happy for a couple days and then they would get bad looking. The only way I can put it, is that all corals, regardless of their normal color, would start turning a dull gun metal blue/grey. Not until I started doing 50%/50% salt did the corals seem to be happy longer. But, everything will start looking really bad if I don’t do the 20% weekly. So my thought is that the contaminent takes a few days to start harming the coral and until then, the corals are happy with the new trace elements. That’s just my observations.