I'd encourage to still do the metal checking I suggested (back of the toilet), ID the actual units on your pool (per Waterbear), set yourself up to do REAL testing yourself, and SERIOUSLY consider just saying NO! to metal ("mineral") treatment of pools.

Metals, concrete based pool finishes (like Pebble-Tec) and pool owners who are particular about finish appearance are NOT a compatible blend. But, by the time you realize that the problem is IN the finish, and not just in the water, you will have a hard time ever getting back to the starting point you're at right now. If you actually have ozone, and want to continue using it, that's fine, as long as you stay on top of your alkalinity. But, there's no way to do metals -- from cartridges, ionizers, pellets, algaecides or what-not -- and maintain a pristine finish.