hth® calcium hardness increaser, 4 lbs.

hth® calcium hardness increaser is used to raise the calcium hardness of swimming pool water.


About This Item

hth® calcium hardness increaser is used to raise the calcium hardness of swimming pool water. Low calcium hardness may cause the pool water to be corrosive, resulting in damage to pool surfaces and equipment. Plaster  finish pools may be etched or stained if the calcium hardness of the pool water is not properly adjusted. The calcium hardness of chlorinated pool water should be maintained in the range of 200-500 ppm.        

  • Raises calcium hardness levels
  • Prevents corrosion of metal & plaster surfaces
  • Compatible with salt systems
  • Apply directly to pool


Balance With HTH Calcium Hardness Increaser

Raises Calcium Hardness of Pool Water

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

man and lady with baby swimming underwater

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. 

pool water filter

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 Increaser

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1. Test pH Levels and Hardness

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

2. Determine Number of Pods

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

3. Apply Directly to Water or Skimmer

With the pump running, add pods one at a time to pool skimmer, or directly to pool water by throwing into the deep end of the pool. Use a pool brush to disperse any undissolved chemicals. 




Day After

boys playing on float in the pool