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What is Chlorine Demand?

Chlorine demand is/are substances in the water that are “demanding” a reaction with chlorine. Once these reactions occur, little to no chlorine is left to disinfect. When dealing with chlorine demand, ENOUGH CHLORINE HAS TO BE ADDED T SATISFY CHLORINE DEMAND AND PROVIDE PROPER DISINFECTION.

What determines chlorine demand?
            These are many factors that determine the chlorine demand for each individual swimming pool. These can range from the size of the pool, the bather load, and even factors that are out of your control such as sunlight and the number of leaves that fall into the pool. It is in your best interest as a pool owner to familiarize yourself with the main reasons that directly affect your pool’s chlorine demand. By doing this, you can help to prevent algae growth, make your chlorine most effective, and eliminate future stress down the road.

  • Pool size- The greater the volume of a pool, the higher the chlorine demand is. For example, for a 10,000-gallon pool to have a chlorine level of 2ppm, it will only require two pounds of granular chlorine, but for a 30,000-gallon pool, to reach a chlorine level of 2ppm, it will need six pounds of chlorine.
  • Bather load- The number of people that swim in your pool can greatly lower chlorine levels. This is because the chlorine is working harder to fight off bacteria, thus using your chlorine quicker. For example, after a big swim party, your pool might have little to no chlorine in it, because the chlorine was fighting off the organic waste created from your guest.
  • Sunlight- The UV rays from the sun will burn up and disintegrate most, if not all, of the chlorine in your pool. To prevent this from happening make sure your pool’s cyanuric acid levels are between 30-50 ppm.
  • Algae- Having algae in your pool is one of the quickest ways to lose chlorine. Algae can bloom whenever the water is out of balance, warm temperatures are present, and when nitrates and carbon dioxide are present.
  • Organic Materials/ Wash-ins- This can be caused after heavy rainfalls when organic materials from the lawn or garden slide into the pool. Leaves that fall into a pool can also raise your pool’s chlorine demand.

Treating chlorine demand
            The easiest way to determine how much chlorine you should be adding is to bring in a water sample to Central Jersey Pools for a free water analysis. Be sure to inform our retail staff about algae being present, future plans for a swim party, or any other factors that would affect your chlorine demand. From there, we can recommend effective products that will keep your pool crystal clear, and free from bacteria. 
– The information in this brochure is true and complete to the best of our knowledge, but without guarantee on the part of Central Jersey Pools, or on the part of any of its employees who disclaim all liability incurred with the use of this information.
Contact Central Jersey Pools at 732-462-5005

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