Chlorine Levels in Pool Are Too High

There are a number of issues that can confront the owner of a swimming pool when it comes to her pool. One issue that particularly confounds pool owners has to do with high levels of chlorine in their pools. As a water disinfectant, chlorine is renowned for its effectiveness and relative ease of use. However, there are several conditions that can cause a pool's chlorine levels to remain too high for both safety and swimmer comfort.

High chlorine levels can make a pool too uncomfortable for swimming.


In many cases of excess chlorine in a swimming pool, the cause can be as simple as the swimming pool not being used enough. Chlorine is still being added to the swimming pool, but it isn't being used up in disinfection because swimmers aren't dirtying the water. Also, pool chlorine is dissipated by sunlight and warmer water temperatures. If a swimming pool is always covered and kept too cool, the chlorine will work very slowly, if at all.

Excess Chlorine

Swimming pool owners are advised to strive to keep their pool water's chlorine levels at about 2 parts per million (PPM). A good working range of chlorine in a swimming pool is approximately 1 PPM to 3 PPM. A swimming pool that's much above about 5.5 PPM in chlorine level will become too uncomfortable for swimmers to use. For example, too much chlorine in a swimming pool can cause issues such as eye irritation and irritation of mucus membranes.


The solutions to excess chlorine in a swimming pool are relatively easy to carry out and only require that the pool be used more often, for one. Other methods of lowering available chlorine levels in a pool include allowing it to get more sunlight and warmer water temperatures. You can run warm tap water into your pool, which will work to lower chlorine levels. Lastly, to lower chlorine levels effectively, don't add more chlorine until the level declines to about 2 PPM.

Chemical Solution

There is a specific chemical-based solution to lowering chlorine levels in a swimming pool that involves the use of sodium thiosulfate. An effective chlorine neutralizer, sodium thiosulfate will lower available chlorine in a swimming pool by about 1 PPM per packaged dose. It's available at many swimming pool supply stores and is typically marketed as just "chlorine neutralizer" or by its chemical name. Remember to always use any swimming pool chemical only according to the manufacturer's directions.


Two other factors will affect available chlorine demand in a pool. The first factor affecting pool chlorine levels is pool pH balance. If swimming pool pH is above 8 — 7 to 8 is recommended — chlorine will work very poorly or not at all. The second factor that affects a pool's chlorine demand is an excess of chlorine stabilizer, such as cyanuric acid (CA), in the water. The ideal swimming pool CA range is 30 to 50 PPM, with 150 PPM being the maximum.