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Certified Swimming Pool Stain Removers
Calcium Hardness Calcium hardness (CH) is the measure of dissolved calcium in your pool water. Calcium in this form is not visible to the naked eye.  The terms soft water (low CH) and hard water (high CH) are terms used to express the calcium hardness of water.  If the calcium hardness of your pool water is too low it will ‘seek’ calcium and attack (or etch) the plaster finish of the pool surface and equipment.  Some mistakenly believe that if their pool has calcium scale build-up that lowering the calcium hardness will solve the problem.  This is not the case.  In many cases, lowering the calcium hardness can make scaling issues worse and cause stains to appear.  Calcium hardness can be increased by adding calcium chloride to the pool water. If the calcium hardness is too high then the water will be scale forming.  This is because the water wants to deposit the excess calcium.  This leads to clogged filters, cloudy water, rough pool surfaces and eye/skin irritation.  Lowering calcium hardness is very difficult to do as it generally involves partially draining and replacing some of the water in your pool.  Some chemical additives claim to be able to lower calcium hardness but our experience has shown that very few actually work. As with all water chemistry, the ideal is to have the calcium hardness in balance.  The suggested range of calcium hardness is 200-400ppm.