Stabiliser (CYA, cyanuric acid) helps reduce chlorine residual loss from ultraviolet light. The stabiliser level should be maintained at 30 – 40 ppm or higher. Add 400 grams of BioGuard Stabiliser per 10,000 litres to establish the ideal level of 40 ppm. The stabiliser level should not need to be replenished if a stabilised chlorine is being used. Stabiliser is only depleted through actual loss of water, such as through backwashing or splashout. Stabiliser is not necessary in spas, although stabilised products like Spa Lite and Brominating Concentrate can certainly be used. Brominated pools cannot be stabilised with cyanuric acid, and Stabiliser is not needed in biguanide pools.

Low Stabiliser:

Low stabiliser levels can result in increased chlorine consumption. However, with chlorine demand situations, the stabiliser test reading may be masked. If the stabiliser reading disappears suddenly and a chlorine reading is not being maintained, do not add stabiliser until the chlorine demand has been eliminated.

High Stabiliser:

Stabiliser readings higher than 70 ppm have an effect on the total alkalinity test. For every 100 ppm of Cyanuric Acid (CYA), the tested total alkalinity will increase by 30 ppm. However, this 30 ppm is not an effective buffer. This false total alkalinity reading is automatically taken into account with the input when an analysis is performed in ALEX.

High Stabiliser and Health Departments:

Many state and local health departments do not allow levels of CYA higher than 100 ppm. While there is some evidence to suggest that higher stabiliser levels do slow down the bactericidal activity in certain water conditions, this is not the case in swimming pool environments. Actually, research shows that in a swimming pool, higher levels of CYA in a properly balanced pool increase the bactericidal activity of chlorine. Levels as high as 400 ppm have been demonstrated not to have a negative impact on overall pool performance.

If you need help in working with your local or state health department concerning this, contact your Business Development Manager or Marketing Services.