Because chlorine can dissipate under the ultraviolet rays of strong sunlight, HTH® Classic should always be added in the early evening so that the job of disinfecting the pool is accomplished overnight. Night-time addition of chlorine allows more effective use of the chlorine for oxidising and disinfecting.

Chlorine loss can be reduced by stabilising pool water with cyanuric acid (pool stabiliser).

In a pool treated exclusively with HTH® Classic, the initial dosage of cyanuric acid (pool stabiliser) should be between 40 - 60ppm.

When using a stabilised monthly floater or stabilised pills, the start-up dosage should be 30 ppm. Stabilised floaters and pills deposit a residual of cyanuric acid in the pool water which gradually build up and if not checked, can reach an unacceptable level.

• Remove the automatic pool cleaner. Backwash and then rinse the filter thoroughly.
  
• Adjust the pH to 7.2.
  
• In the evening, shock treat the pool by adding 3 cups of HTH® Classic or one sachet of HTH® Super Shock It. Run the filter continuously for 12 hours.
  
• Mix the required amount of HTH® Pool Stabiliser in a clean plastic bucket. 1kg of HTH® Pool Stabiliser in a 50 000 litre pool will raise the stabiliser level by 20ppm.
  
• Pour the slurry into the weir and run the filter for at least 12 hours.
  
• Check and correct the pH to 7.2.
  
• Reconnect the automatic pool cleaner.
  
• Thereafter continue with normal filtration and chlorination programme.
  
• Although cyanuric acid is totally soluble, it is very slow dissolving and because of poor solubility, some product may settle on the filter media. Do not backwash for at least 48 hours. If you backwash before product dissolves, you may lose some of the product.

• Pool stabiliser added in the recommended quantities, is sufficient for a whole season. Splash-out and backwashing will reduce its concentration, so a check should be made at the beginning of each season.
  
• If you intend using one of the stabilised products as a sanitiser, at start-up, raise the cyanuric acid level to 30ppm because these products add cyanuric acid to the water as they dissolve.
  
• To ensure that the water does not become overstabilised, always backwash for an extra minute or two. When replacement water is added it will dilute the concentration of the cyanuric acid. Therefore, test the cyanuric acid level at least twice a season.
  
• The chlorine residual level must be maintained at a slightly higher level i.e. between 1.5 - 3.0 ppm if using stabilised products. The pool water should, therefore, be shock treated with HTH® Classic every 7 - 10 days during the summer months.

All dosages are based on an average pool with a capacity of 50 000 litres. Adjust according to your pool size, regional variations and weather conditions.

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