Fins,
I don't have time to describe the difference in CuSO4 and Cutrine, but I'll tell you from a professional's point of view...we don't use anything but Cutrine due to the less toxic properties and effectiveness of Cutrine. It's not as cheap as copper sulfate, but there is a reason for that.
Remember one thing...copper sulfate and Cutrine are not the same thing. Cutrine is a chelated copper which is much less toxic than CuSO4. Cutrine sells a granular form (not copper sulfate) as well. I recommend the use of Cutrine for all algae treatments (requiring copper)...otherwise use Green Clean.
Do your homework before performing the application.
