It was used in a green pool after the addition of hydrogen peroxide, which left it cloudy. It did a pretty good job of collecting dead algae in the filters (they turned completely black!) but because the correct dosage was not used, it was not as effective as expected. So, because it was not used correctly, I cannot know for sure the final result.

I would buy it again in the future, but if you have polyester filters, I would recommend using 2 (one inside the other) and the CORRECT dosage. Then, along with the rest of the instructions in the box, within less than 24 hours, the pool will become crystal clear.