Thanks -

It sounds like I should probably check the alkalinity of the water first, before I try the copper sulfate. I should be doing that anyway, but not sure what the base level should be.

I have a large fountain in the middle of the pond that I haven't turned on this year yet, but I'm guessing that will help with water aeration/oxygen levels that might be lowered by killing off the algae.

http://help.bioworldusa.com/kb/algae-treatment/is-copper-sulfate-toxic-to-fish

Last edited by JohnR; 04/24/19 12:41 PM.