HTH® Calcium Hardness Up

HTH® Calcium Hardness Up is used to raise the calcium hardness of swimming pool water.


About This Item

Low calcium hardness in your pool can cause pool water to be corrosive, resulting in damage to pool surfaces and equipment. Test your water weekly to make sure your calcium hardness levels are between 200 and 500 ppm. If it’s below 200 ppm, add HTH® Calcium Hardness Up to raise calcium hardness levels, and prevent corrosion of metal and plaster surfaces. HTH® Calcium Hardness Up is great for all pool types including vinyl-lined pools and salt water systems.

  • Prevents corrosion of pool surfaces
  • Protects pool liners
  • Helps keep calcium hardness levels between 200 and 500 ppm
  • Great for all pool types including vinyl-lined pools and salt water pools
HTH Calcium Hardness Up helps you stay balanced all summer long


Balance With HTH® Calcium Hardness Up

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Raises Calcium Hardness of Pool Water

HTH® Calcium Hardness Up works by raising the calcium hardness of pool water.  

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Keeps Swimmers Comfortable

Keeping your pool balanced is key to ensuring a comfortable swim for all. In addition to maintaining pH levels between 7.2 and 7.8, make sure the water has enough calcium; 200-500 ppm is the ideal range.

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Protects Pool Surfaces From Corrosion

Balanced pool water also helps protect your pool equipment and surfaces from corrosion, stains or other damage. 

How to Use HTH® Calcium Hardness Up

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1. Test pH Levels and Hardness

Use HTH® 6-Way Test Strips to test the pH level and total hardness. The ideal pH range is between 7.2 and 7.8.

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2. Determine Correct Dosage

Use the label instructions on the back of the pouch to determine the necessary dosage depending on pool volume (gallons) and calcium hardness level from step 1.

ph line graphic item use hth ph up or hth ph down to keep your swimming pool ph levels in range

3. Apply Directly to Water

With the pump running, add granules directly to pool water by throwing into the deep end of the pool. Use a pool brush to disperse any undissolved chemicals.




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