HTH 67289 Swimming Pool Care Algae Guard Ultra, Swimming Pool Chemical, Long Lasting Formula, 32 fl oz

My experience has been that this product works for 3-4 months minimum per application, which is awesome in my opinion. If it’s not working like that, your have other issues with the chemistry in your pool that you need to address first. I also, unfortunately, know this from experience. Get your total alkalinty, calcium hardness, and chlorine stabilizer levels right and this stuff will work for ages. I’ve had a week here and there where I was lazy about chlorine, and it dropped pretty low but I still didn’t get ANY algae, which was an issue before I started using this stuff.This review is specifically for HTH 67289 (the “Ultra”, not the “Advanced”) which contains copper sulfate, the magic ingredient.