Calcium Hardness Testing in Spas & Hot Tubs

Calcium Hardness TESTING

Calcium Hardness Test Kit

Measurement of calcium hardness in your spa is essential to ensure that the water ‘feels’ right and is not causing harm to your spa’s equipment and surfaces.  We have found that this simple ‘reagent’ based test kit is far more accurate than test strips for measurement of calcium hardness.  Testing should be carried out at every water change and monthly thereafter.

To use the kit simply fill the test tube with 10ml of spa water and add drops of the reagent noting how many drops are required to change the water colour from red to dark blue. The number of drops determines the calcium hardness of your spa’s water.

The ideal range for calcium hardness in spas using chlorine, bromine, Spa Frog and Active Oxygen sanitisers is 120 – 500 mg/litre or parts per million (ppm).  For Pristine Blue based disinfection it should be 120 – 250 ppm.  Lower values than 120ppm may result in corrosion of equipment and staining.  Artificially softened water that has a very low calcium hardness should therefore not be used in a spa.

To raise calcium hardness add  a product such as Balance Pak 300 or Leisure Time Calcium Booster.

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