- A chemical pool uses packaged chlorine in the form of sticks, tablets, liquid, pucks or powders to create a residual level of chlorine. Packaged chlorine is not pure, active chlorine; it contains a stabilizer that allows the chlorine to remain in the pool longer instead of evaporating in the sunlight. Chlorine will attack bacteria and contaminates to break them down and remove them from the pool. During this process, and through evaporation in sunlight, chlorine gets used and has to be added again. Chemical pool owners add chlorine every day to maintain a 2 to 3 parts per million (ppm) level.
- During the installation of the saltwater system, massive amounts of salt are dissolved into the water. Each generator will differ, but the general rule is a salinity level of 3,000 ppm or about 25 lbs. of salt for every 1,000 gallons of water. After dissolving, the generator breaks the sodium chloride (NaCl) into sodium and chloride that combines with hydrogen and oxygen in water. This reaction produces the same HOCl as in packaged chlorine. This chlorine, however, is pure and, when the water leaves the generator, the HOCl returns to NaCl. This continuous rotation recycles the salt in the pool and makes chlorine as the generator runs. The continuous creation of new chlorine is similar to a constant shocking of the water, eliminating chloramines. Saltwater systems usually have a lower chlorine level than a chemical pool, around 1 ppm.
- Free chlorine is chlorine available to disinfect the water and keep the pool sanitized. Combined chlorine is in the process of breaking down something and does not affect the amount of free chlorine. When the level of chloramines (or combined chlorine) rise, the gas given off produces the chlorine smell. The mistake people make now is not adding more chlorine to the pool, thinking that the level is too high when, in fact, the opposite is true. The chlorine is trying to destroy something but is combining with nitrogen or ammonia and can no longer work, which is when the pool needs to be shocked to burn off the combined chlorine.
- In some instances; especially hot weather, heavy rains and increased usage, the chlorine level in both pools will drop. The chemical pool owner has one course of action: to shock the pool. This quick-dissolving form of chlorine, different from the regular sticks or tablets, is added to the pool to increase the chlorine level and bring it back in line. The saltwater pool owner can choose to shock the water or to run a boost function on the generator. The effect is similar as the generator will run for a longer time than usual cycle and will increase the amount of free chlorine in the water, removing any chloramines.
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