Bests & Worsts Reviews from Amazon

I bought this product because our fountain had a rough surface and seemed to accumulate green algae very quickly. The first time I used this product, I had cleaned it out the best I could and added the recommended amount. It seemed to really slow the growth of new algae, but it did not diminish the spots that I couldn't scrub out. The next time I cleaned out the fountain, I almost doubled the recommended quantity and found that it did a quite good job of diminishing the existing stubborn spots (though not completely, but quite good) and prevented the growth of new for several weeks. The fountain evaporates and splashes out a lot of water so I expect the enzymes would have done even better if I had regularly added small amounts to compensate for the fresh water I added to replace water loss. I will say that this product works at least as well as other similar products that cost twice as much. I am glad to have it!