Removing metals from pool water without leaving stains behind is not a problem we've fully solved here. So, the truth is, I don't know if it would have been better to keep filtering, or to add the HEDP, and finish removing later. Having the HEDP in the water can lift recent stains back into the water. So . . . it may well have been better to add the HEDP.

Hopefully in 2015 we'll have a clear and complete program for managing metals in pools. But this summer, we're going to be experimenting to find the best way(s).

I've started a collection of all the pool chemicals out there -- well, MSDS, sales, and label sheets -- so we can ID specific chemicals hiding behind brand names. (Over 8 GBytes of files, so far!) That's a first step to helping people. As long as the products are mystery products, we can't apply a systematic approach to the chemistry.