In The Swim Pool Shock – 68% Cal-Hypo Granular Sanitizer for Crystal Clear Water – Defends Against Bacteria, Algae, and Microorganisms - 12 X 1 Pound

These are much cheaper and work better than in store ones. Gets the green out pretty quick.

I’ve always been happy with In The Swim pool products and this is no exception. This along with a stabilizer keeps my chlorine levels in check. Tablets are made strong enough so that there is minimal breakage. They last a long time without breaking down.

OH BABY, worked as expected.

Good product and good price

I picked up this pool shock specifically to keep on hand for emergency situations rather than for pool maintenance. My goal was to have a reliable, long‑lasting sanitizer I could mix with water if needed, and this product fits that purpose well so far. The individually packaged 1‑pound bags make storage simple, and the high concentration means a little goes a long way. It seems durable and stable enough to keep on the shelf until I need it, which is exactly what I was looking for. Since I’m not using it in a pool, I can’t speak to its performance there, but as an emergency‑preparedness item, it’s been a solid addition. I’m giving it four stars mainly because I haven’t had to rely on it in a real emergency yet, so long‑term effectiveness is still something I can’t fully judge. Overall, it’s a practical product to have on hand, and it gives me some peace of mind knowing I have another option if I ever need to sanitize water quickly.

Good product at a good price

Buy this every year to open my pool with. It cleans my water and raises the chlorine level to help clean the water. I continue to shock the pool throughout the summer.

Great product for algae removal and it clears up the water.when I see even a thought of algae I scrub the walls and add the shock treatment and the next day it’s all beautiful again.