HTH 67084 Pool Care Algae Guard Advanced, All Algae Eliminator for Swimming Pools - Fast-Acting, Destroys & Prevents Green, Black & Mustard Algae, Keeps Pool Water Crystal Clear, 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.

Although the price would seem to be high the reality is it is concentrated and you need a lot less as compared to other algaecide products that are typically sold in the gallon size. This is a better buy and works well.

Greatest stuff on planet earth!Clear, Clean Water!It was cloudy all summer, if there’s white algae, couldn’t get rid of it, end of summer found this and dumped 2 bottles into the pool and crystal clear!Bought more and am ready for this summer!

It instantly kills the green alge in the pool, it does however make the pool cloudy.

I used this in my pool yesterday and it seems to really be doing it's job killing off the algae. I have an almost 50 year old pool and have issues every year and this seems to be really helping!

HTH Algae Guard is a game-changer! As always, it arrived quickly from Amazon, and I was able to treat our green pool right away. Today is just day 2, and I can already see the bottom of the pool again—huge improvement! I highly recommend this product if you’re dealing with algae and want to get your pool swim-ready fast!

More volume for cheaper than Walmart

I have been battling algae for 6 months! I decided to try a new brand. Cleaned my filter (again!), brushed and vacuumed my pool and added the entire bottle and let the filter run over night. The algae has been gone for 7 weeks so far. I am adding phosphate remover and chlorine regularly and have not seen any algae return after one treatment.