[bertoni]

I am not sure what might be the issue, but I can't think of anything that would bind the calcium so that it could be read by the test but not used by corals. Strontium is chemically very similar to calcium. If it's actually that high, which I doubt, it would be measured by the calcium kit, most likely, as it's very hard to test for just one of the two. Lithium that high, if real, most likely would be from a bad batch of salt. I might try a new batch of salt, and see what changes that makes.