How Do Salt Systems Work? Saltwater systems have been becoming increasingly popular in recent years. They offer a number of benefits over a regular chlorine pool.
Saltwater swimming pools draw on dissolved salt in the water to generate chlorine. The salt cell or generator utilizes a process called electrolysis to break down or separate the salt also known as sodium chloride or NaCl in the water.
The chemical reaction created by electrolysis produces chlorine in the form of sodium hypochlorite and hypochlorous acid. These sanitizing / disinfecting / oxidizing agents are the same as chlorine commonly used in swimming pools in solid and powdered form. This means a saltwater pool is not actually chlorine free. It simply utilizes a chlorine generator instead of being dependent on chlorine added in other forms.
An important difference between a non-saltwater pool and a saltwater system is that saltwater pools have reduced amounts of chloramines. Chloramines are a by-product of oxidation or the breakdown of matter in the pool water and are the primary cause of eye irritation and a pungent “chlorine” smell. The reduced chloramines in a saltwater pool are one of the biggest advantages. The process of electrolysis oxidizes or eliminates chloramines in a much a similar manner as traditional chlorine shock.
Typical residential salt systems request the salt levels in the pool to be in the 2800 – 4200 parts per million range. This is much less than the ocean, which has a salt level of approximately 35,000 ppm.
At Gabe’s Pool Service we manage toward a salinity level of 3,000 to 3,500 parts per million (ppm) or 3 to 3.5 grams per liter in the pool water. While we utilize the on board salinity reader provided with most salt systems we also use a separate independent digital salt reader to test every time we perform a service or maintenance visit to a saltwater pool. This helps us verify the reading because on board readers can become inaccurate as seasons go by.
Heavily concentrated salt should not be poured into the skimmer as it could cause a fuse to blow in the salt cell due to over-conductivity. The proper method of adding salt is to pour it across the steps or pool floor and brush it in until it is fully dissolved.
Even with the daily chlorine generation via the salt cell chlorine levels can become lower in a saltwater pool. When they do the leading cause is typically low salt. Other causes include low stabilizer / cyanuric acid, lower concentration of salt due to splash out, backwashes, and dilution via a variety of sources including rainwater, evaporation etc.