I used cupric sulfate as an algaecide in my swimming pool for a while without problem. I was adding a very small quantity of it (one teaspoon when the season start and 1/4 teaspoon whenever I add water.) However, a "swimming pool expert" told me I should not, that it is dangerous, and various others claim (Obviously, he wanted to sell me his own algaecide). I had many problem this year to keep my swimming pool clear of algae, So I'm considering returning back to cupric sulfate.
So, I made my own search and this use copper sulfate seam quite controversial:
Does someone has an objective notice for that?