Clorox® Pool&Spa™ Swimming Pool Calcium Hardness Increaser, Prevents Corrosion, Etching and Staining, 4LB (Pack of 1)

This hardness increase works every bit as well as the premium products from a fancy spa supply house. Name brand product, great value, easily applied and with two internal packages, useful for a good long time.I did admittedly transfer this product to a sturdy plastic canister for better moisture protection and easier storage / application.Would easily recommend and will certainly order again.

Keeps the pool water sparkling clear. Leaves no residue

I used this to increase my calcium hardness over a month ago and my level is still perfect!! The package comes with a lot of product so this will last me a while. Since hot tubs/spas are hard to maintain, any time I find an easy, long lasting and efficient product I am a happy camper!! 10/10 will buy again!!!

You can get better chemicals. I feel like you have to use a extra amount to get the job done. But it will get the job done.

Clorox pool products are the best of the best. No comparison. Spend the few extra bucks on it, it’s been worth it!

I used this in my hot tub to harden the city water. Worked just as good as the expensive stuff from there and was bigger volume in bag verses their little bottle of it.

I’m a big fan of Clorox Pool&Spa products, and the 2-in-1 Perfect Balance is no exception. It effectively maintains balanced pH and alkalinity levels, which helps prevent skin and eye irritation and reduces overall pool maintenance. The product is easy to use—just apply it weekly to keep your pool water clear and comfortable. It also helps extend the life of your pool equipment by preventing corrosion. Highly recommend for hassle-free pool care.

Have been unhappy with local pool supply's chemical costs. Now buy most online for much better price and get same quality.