In The Swim Super Pool Shock Swimming Pool Sanitizer - Fast Dissolving, Non-Stabilized - 70% Available Chlorine - 12 x 1 Pound Bags

I had a really bad infestation of mustard (or yellow) algae. I mean it was all over the walls and the water so foggy you couldn't see the main drains! I used this stuff along with McGrayel Algatec - brushed down the walls a couple of times a day, and within a couple of days had crystal clear water. It took a few more days and a couple more applications along with more brushing to completely clear it off the walls, vacuum, hose, everything. Very impressed with this stuff and would recommend to anyone having problems with algae, especially in these warmer months. Don't forget to disinfect any pool toys and wash any clothes that were in the pool before it was clean. You'll just introduce that s..t back into it.

I have been using this product for about 2 years now. I'm not sure what all the so-so reviews are about. As a new-to-pools owner, I'll admit it took a while for me to figure out all the chemical interactions and which was right for my pool. Forgive me if this states the already known, but I figured I put this here in case anyone else is new too. This product is Calcium Hypochlorite. It is one of the few non-stabilized chlorine based shocks. Most other chlorine based shocks contain some cyanuric acid (stabilizer). It's also one of the highest concentrations available (more chlorine, less byproducts). Why choose a non-stabilized chlorine shock? I use and auto feeder with tri-chlor pucks for my normal daily chlorination. These already contain stabilizer, so I do *not* want to add additional stabilizer when I shock. If I did, my cyanuric acid (CYA) levels would rise far too fast which would mean more frequent partial drain and refill of the pool. Also of note - when shocking, but especially when using non-stabilized shocks: always shock at night. Two things kill chlorine levels: algae and sunlight. Let the shock work against the algae, not fight the sun.

This is the first pool product that really got rid of the algae in my pool. It has taken 2 months. I am very happy. It shouldn’t be that! It dissolved easy, worked as stated, great value. I could have saved $200.00 if I have bought this first.

My pool was dark green and I put 6 bags in one night and 6 bags in the next night and it killed all the algae and pool looks great today.

WAY over priced but nothing we can do about it since everyone has jacked up their chlorine prices. One thing I don't like about ordering this product is that In The Swim is now owned by Leslie's (where I never shop at because they always have the highest prices). If they don't reduce the chlorine shock price soon (the under-stocking problem presumably has been resolved??) I'll be ordering from somewhere else. Am considering filling pool with dirt to avoid the high cost of products now.

I've been wasting a lot of it by showing people what happens when you mix with brake fluid in a plastic open drink bottle. Careful, it produces a blow torch like orange flame about 3or4 ft high in around a min & a half

Good value and gets the job done with keeping the algae down.

Shock we’d started using was just not working well. Brand we’d been using was discontinued locally. So switched to available. We’d been having algae on our pool steps since switching …. NEVER had that happen. We’ve had the pool for 21 years now and issues were/are not normal. Started using this with much success. The available chlorine is key! No more green algae!!! Will be using this from now on!