Calcium Increaser, Liquid Spa Water Hardness Booster for Hot Tub & Spa, Supports Equipment Longevity, Enhances Water Balance, Reduces Foam, Salt System Compatible, 32 oz

Seems to help my other chems work more efficiently. I tried another brand but had to use way more to get to the same levels. Leads me to believe that there are clear quality and concentration differences among the various companies that sell this stuff. I highly recommend it.

Hot Tub Things products are great. They cost less than most retail store options and are excellent quality. They keep my hot tub clean and safe!

Use this in our hot tub. Great product great service.

Good water in the tub absolutely necessary.

Works as described.

Works great

I received this with the seal open. Obviously I’m skeptical this is actually the product I purchased. Sketchy.

works as it should