Do these things work?

[chem geek]

They are correct that the copper ions will inhibit algae growth so that will let you operate at a lower FC/CYA ratio than you would otherwise need to prevent such growth, but the risk is that if the copper ion level gets too high or the pH gets too high, you can get copper metal staining, especially on plaster and fiberglass surfaces (less risk with vinyl) and people with blond hair can get a greenish tint in their hair.

Chlorine alone can prevent algae growth, disinfect the pool, and oxidize some bather waste so there is no need for other products. If one really, really wants to operate at a lower active chlorine level, then there are many algaecide alternatives other than copper ions. Phosphate removers sort of work but are expensive and temporarily cloud the pool. Linear quat algaecides can foam. Polyquat 60 is the only one we'd recommend because it doesn't foam and more slowly breaks down from chlorine though it is more expensive than linear quat algaecides. Again, this isn't needed unless you are absolutely set on having a lower FC/CYA ratio.

Note that the minimum FC/CYA ratio proposed on this forum, that is roughly 7.5%, has the same active chlorine level as an FC of only 0.07 ppm with no CYA so I don't know why you'd want to get much lower than that for extra cost.

[Bosch232]

Thanks for all the info. I don't think I'll be following my colleague's footsteps.