Don’t bother, your tap is probably better than my rain water up there in Scotland lol. Your water is perfectly suited to South American species. Only reason my fish are happier and healthier than they were previously is they’re not suited to my hard tap.Good point, maybe I don’t need to as tap water is as soft as it gets, I was swayed by reports of healthier fish and a vague notion of natural is better but maybe its just not needed.
What I’d give to have your tap water!