I used [cupric sulfate](http://en.wikipedia.org/wiki/Copper%28II%29_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:

* Some say [it is ok](http://www.sciencebase.com/science-blog/copper-sulfate-swimming-pool.html)
* Some say [dont use it](http://www.askalanaquestion.com/pool_algae_control_products.htm)
* Some say [maybe](http://swimsuits.lovetoknow.com/Copper_Sulfate_Crystals_Use_in_Swimming_Pools)
* Some [are even more confusing](http://wiki.answers.com/Q/Can_you_use_copper_sulfate_for_algae_in_your_pool)

Does someone has an objective notice for that?