Our pond was really green after the ice melted. We had some Tetra Pond Algae Control(I see Amazon has it) we had gotten last fall, but had not used yet. Have applied it twice now and it has really cleared up the pond a lot. You put it in every 3 days at first. Sort of have some foam/bubbles on top, but if your filter is going they soon clear up. We’ve had a pond for 15 years and this is the best product we’ve found to de-green the pond. Will continue to use it and see how it works out. We also have a filter and a UV filter.

Is it fish safe?

Yep, they seem fine, says fish safe on it. Not good for shellfish.

Pond is clear as a mountain stream. Now I can see all the dead frogs on the bottom…