Why Is the Chlorine Stabilizer Not Dissolving?

Maintaining pool water quality can be a challenge, particularly during the summer months when sunshine depletes chlorine levels. Insufficient chlorine leads to inadequate sanitation and can result in algae growth. To minimize chlorine loss -- and reduce the likelihood of having to close the pool while restoring water quality -- pool owners add stabilizer to the water.

The most common pool stabilizer -- or conditioner -- is cyanuric acid, a slow-dissolving powder or granular product. Pool owners should maintain cyanuric acid levels of 30 to 50 ppm. If the level is too low, there will be insufficient protection against ultraviolet light and chlorine will dissipate. Too much cyanuric acid, on the other hand, can lock the chlorine and reduce its effectiveness as a sanitizer.

Because stabilizer granules are slow to dissolve, certain manufacturers recommend dissolving cyanuric acid in warm water before adding it to the pool. Others recommend broadcasting the granules over the pool by adding the product near a jet or return line. Some suppliers suggest adding granules via the skimmer so that they dissolve in the filter, releasing stabilizer to the pool over several days. Pool owners should avoid backwashing the pool for three days after adding stabilizer, allowing time for the product to fully dissolve and circulate.

If you have added the product direct to the pool, you may be left with a quantity of undissolved granules. These granules will sink to the bottom of the pool, where they may take several days to dissolve. The presence of these granules does not indicate that you have added too much stabilizer -- the product is slow to dissolve, particularly when static. You can speed the process by agitating the granules with a brush so that they circulate in the pool water. You may need to repeat the process several times before all the granules dissolve, and you should avoid using the swimming pool during this time.

Test the pool water at the beginning of the season, and add cyanuric acid if necessary. Because pool chemicals do not destroy cyanuric acid, the level reduces only if you add fresh water to the pool following splash-out or backwashing -- so you will need to add only small quantities of the product during the swimming season. Always follow the manufacturer's written instructions for use and storage of pool products. Some pool experts caution against adding pool chemicals via the skimmer -- so check with your pool equipment supplier before doing this.