SpaGuard Calcium Hardness Increaser, 12oz

Sku: 42636BIO
(1 customer review)

SpaGuard Calcium Hardness Increaser

Prevents corrosion of equipment
Prevents degradation of spa surfaces
1 tbsp. per 100 gallons increases calcium hardness ~25 ppm


SPAGUARD CALCIUM HARDNESS INCREASER raises calcium hardness in spa and hot tub water. The desired calcium level in spa water should be 100 to 200 ppm (parts per million). Low calcium hardness below 100 ppm could cause spa water to be corrosive which may damage spa surfaces and/or equipment.

MEASUREMENT AND DOSING: Use all level measurements. 3 teaspoons = 1 tablespoon; 2 capfuls = 1 tablespoon; 1/4 cup = 4 tablespoons.


  1. Use an accurate test method to determine calcium hardness of water.
  2. Determine the required amount of SPAGUARD CALCUIM HARDNESS INCREASER needed to adjust the calcium to maintain a reading of 100-200ppm.
  3. With pump running on high speed, scatter the required amount of product over the spa water and continue running pump for 30 minutes. Do not pre-dissolve this treatment as heat is generated when it contacts water.
  4. When using SPAGUARD CALCUIM HARDNESS INCREASER, measure carefully. Inaccurate measuring could result in a calcium hardness level other than desired.

Reference Numbers: R0812 L42636BIO 42636BIO

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1 review for SpaGuard Calcium Hardness Increaser, 12oz







Reviewed by 01 customer(s)

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  • RT

    helps with TA

    This helped me achieve the Total Alkalinity I needed when I changed my spa’s water. Glad to have it on hand

    September 13, 2023

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