O-Rings & Seals for Pool & Spa Products

The type of chloramine, monochloramine, used to treat municipal water is different than the dichloramine and trichloramine commonly formed in swimming pools. When chlorine is added to a swimming pool, two chemicals are released, hypochlorous acid (HOCl) and hypochlorite ion (ClO-). Chloramines are formed during a reaction between the hypochlorous acid and ammonia. Ammonia is a component of sweat and urine. The type of chloramines formed, monochloramine (NH₂Cl), dichloramine (NHCL₂) and trichloramine (NCL₃), is determined by chlorine to ammonia-nitrogen ratio and the pH level of the water.

Trichloramines are more responsible for that chlorine smell around a swimming pool than the actual chlorine itself and can be an indicator that the pools chemistry is out of balance. Tricloramines off gas in to the air especially around indoor swimming pools with poor ventilation. They’re heavier than air and lay around the surface of swimming pools unless there is adequate ventilation to blow them away. Trichloramines can cause respiratory problems and corrode metals in and around pools.

Nitrile and EPDM with a sulfur cure are the most common rubber materials used in the pool/spa industry. Nitrile and EPDM haves broad temperature ranges. Nitrile ranges from -40°C [-40°F] to +100°C [+212°F] and also works well with most oils and greases. EPDM ranges from -55°C [-67°F] to +125°C [+257°F] but is not compatible with most oils and greases but it’s the recommended material for use with water, however, you may need a different material depending on the chemical the seal will be exposed.