Part of the problem is that copper "mineral" systems can be effective against algae, but they have almost no effect on bacteria and viruses that may be in the water that we can't see. Thankfully Chlorine is effective on all three, so in a Chlorine only pool we can use the lack of algae as a proxy for telling that our Chlorine level is high enough to be effective not only against algae, but also the vast majority of those bacteria and viruses that we can't see. So when you see this claim towards great reduction in required Chlorine with mineral systems, you have to ask yourself do you want only clear water, or do you want safe clear water? If you want safe clear water steer away from any mineral system as they may remove a potential warning sign about your water being un safe.
