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

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

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.

Always great quality from InTheSwim products. Little slow on shipping this time. Took an extra couple of days.

This product is better than similar products in performance and cost. It keeps the pool clean and clear. It has the right amount of calcium hypochlorite to do the job.

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.

This product works great.