I've got a 180 gallon mainly sps tank that has been doing very well until about a month or so ago The colors of my acros slowly lightened and a couple of them almost bleached. I attributed the issue to low potassium and have been dosing quite a bit. Come to find out that my Triton ICP reported Potassium to be 490, a new potassium kit confirmed the high readings as well. I was basing my correction on a faulty test kit... as my corals started to look worse I added more potassium, I finally started to question the accuracy of my test kit and backed off of the potassium until the ICP test results came back. Well, I'm now in a mode to balance my tank with multiple water changes. I also found that I have elevated Lanthanum and I can't figure out where it has come from. I had a gyre impeller rust in my tank, I think I caught it fairly early... could that be the issue? I also added a single small rock that I have been treating with pool phosphate remover in a bucket for the past few weeks... I rinsed the rock very well before putting in my tank, I can't see how that could be the issue, but I guess its possible. I just finished a 30 gallon water change, Triton recommends that I complete 6 weekly 30 gallon water changes. I'm hoping the water changes will lower my calcium and mag and raise strontium a bit as well. Any thoughts?