My worry is definitely my more sensitive Acropora than my fish, but I am guessing from what you are saying that it should be safe to dose water change water since I will be removing water at the same time
The metals source is a bit of a long story. The tin showed up in my RODI water as well, so first I fixed that. It was a float valve that was made for reefing and had no rust, but when I removed it, the tin went away, but the tin in the tank never cleared. I searched and searched and finally found an old jebao pump that had a metal clip on it. I have several and the newer ones dont have this. I missed it the first time I went through my pumps. So I have all high end equipment except these pumps, and they are what caused me issues! Anyways, the aluminum is from marine pure. I had a ton and I purchased it from Amazon. My understanding is that all marine pure can elevate aluminum, but some of the Amazon stuff was fake and really elevates it. I knew it was a problem, but was scared to remove my bio filter in it, so I have been gradually removing it. I usually had been doing daily water changes and I think this had kept most of this from hurting my Acropora, but during the Fluconazole treatment the acros started losing color and polyp extension. Some of my easier Acropora like birds nest and Stylo stn at the bases. I sent an ICP to the ICP in Colorado since they get the results quickly, and my tin is gone, but my aluminum has jumped to 160 which is very high and more than double my last ATI result. I have now removed all marine pure and been doing very large water changes and my Acropora are looking better. I have sent another ICP to ATI so that I can verify results with the same company I had been using, but I anticipate the results will be much better. I might wait another week and then try the Fluconazole again.
Thanks for the advice, sorry about the long post.
David