Third, some changes can be deleterious to the people in the water as well as to the vessel itself and its equipment. To prevent illness and material damage, the water's characteristics must be monitored routinely. This is the purpose of a test kit. The results of your tests will tell you when and how much chemical treatment is necessary to restore your pool or hot tub to a sparkling clean state. Water cannot stay sanitary by itself.
Sanitation is achieved with the addition of a disinfectant, most commonly chlorine.
The chlorine will react immediately with contaminants that are introduced to the water until its fighting power is all used up. Taylor's DPD chlorine test can. With the results of a DPD chlorine test in hand, you will be able to calculate how much chlorine must be added to the water to bring the sanitizer back up to a safe range. Balanced water is water that will neither corrode nor scale the pool or tub's surfaces or equipment. A change in one factor can affect all the others.