The Ultimate Hot Tub Experience

SpaGuard Spa Calcium Hardness Increaser


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SpaGuard's Calcium Hardness Increaser enables spa owners to increase their calcium hardness with this easy to use granular formula, which will boost your calcium hardness to above the danger zone, where low levels cause extensive corrosion of plumbing, jets, fixtures, and tub surfaces. Calcium Hardness Increaser helps raise the calcium level steadily so you don't get too much calcium and start developing scale build-up and cloudy water. The optimal calcium hardness level is 200-400 ppm, while anything below 100 ppm will cause corrosion.


Routine Maintenance:

1 tbsp per 100 gallons of water will raise hardness by 25 ppm.


  1. Use an accurate test method to determine calcium hardness of water.
  2. Using the total hardness test results determine the required amount of SpaGuard Calcium Hardness Increaser needed to adjust the calcium to maintain a reading of 100 to 200 ppm. For spas on the BioGuard SoftSoak program, adjust the calcium hardness level to maintain a 200-300 ppm reading.
  3. With pump running at high speed, scatter the required amount of product over the spa water and continue running pump for 30 minutes.
  4. Do not predissolve this treatment as heat is generated when it contacts water.
  5. When using SpaGuard Calcium Hardness Increaser, measure carefully.
  6. Inaccurate measuring could result in a calcium hardness level other than desired.


Additional information


12 oz