Tablets containing calcium hypochlorite or trichlor are effective sanitizers. Depending on the type of chlorine tablet selected the other chemicals required may vary.
If stabilized chlorine tablets (trichlor) are used, which will lower the pH, it will require the addition of a base material or caustic like 'alkalinity increaser' in order to raise the pH.
If unstabilized chlorine tablets are used, it will require the addition of an acid to lower the pH.
Cyanuric acid used in stabilized chlorine tablets will stabilize the effect of chlorine as a sanitizer. As additional chlorine tablets are used in the pool, the cyanuric acid will continue to lower the pH and reduce the effectiveness of the chlorine. This can allow algae to grow, cause “cloudiness” of the water and increase chlorine demand. Using stabilized chlorine products may require super chlorinating or “shocking” the pool to raise the chlorine levels to the effective concentrations. Liquid chlorine bleach is recommended for shocking the pool. Additionally, it will help raise the pH of the pool. However, a base or caustic material like alkalinity increaser may also be required to raise the pH to its optimum level for proper sanitizing of the pool.
Periodic testing of the pool water for pH and chlorine concentration is essential. If a stabilized form of chlorine tablet is used, the pool should also be monitored for cyanuric acid.
For unstabilized chlorine tablets the other chemicals needed are an acid for lowering the pH or a base material like alkalinity increaser to raise the pH.
Chlorine Tablets: Maintenance Requirements Long Term Costs