As we begin another season in the recreational water industry, NSF International is providing this important safety alert.

Over the past several years, NSF has received reports of some distributors supplying chemicals that are either incompatible with the chlorination systems used in swimming pools and spas, or that do not meet NSF/ANSI 50 quality standards, which verify and certify chemical delivery using a specific system. This can pose potential hazards to aquatic facility staff members and pool users. Using only the manufacturer’s specified chemicals in chlorination systems is the most effective way to avoid problems and stay in compliance with state and local codes applicable to flow-through chemical systems.

NSF certifies flow-through chemical feeders to the requirements of NSF/ANSI 50, the American National Standard for pool, spa and hot tub equipment. Feeders are certified for use only with chemicals recommended by the manufacturer of the feeder. All NSF/ANSI 50 certified feeders must have a data plate that states: “Use of chemicals other than those recommended by the manufacturer may be hazardous.”

NSF’s certification of feeders is void if other chemicals are utilized. This is because using one form of chlorine compound with a feeder designed specifically for use with another compound could cause an incompatibility issue resulting in fire, explosion and/or generation of poisonous gases. There have been cases where operators have inadvertently mixed incompatible chemicals such as calcium hypochlorite and trichloroisocyanuric acid, which results in an explosion. Also, the potential for inconsistency in chemical concentration resulting from the use of an incorrect chemical type, configuration or brand could result in inadequate or excessive chlorination.

More Information

  • View NSF/ANSI 50 certified feeders and use restrictions in NSF’s listings by selecting Flow Through Chemical Feeding Equipment as the Product Type.
  • Learn more about pool safety from the U.S. Consumer Product Safety Commission.