There are an estimated 1.3 million saltwater swimming pools in the United States, with 70 percent of all new pools being built falling into that category. Lower maintenance and less skin and eye irritation from chemicals are among the reasons more people have chosen saltwater pools over others. However, pool owners, retailers and builders have reported problems that should be evaluated by anyone considering a saltwater pool.
Saltwater systems produce chlorine through an electrolytic cell. If the sodium hypochlorite levels get too high, the pool water can become extremely overchlorinated and corrosive. Corrosion is a frequent problem with saltwater pools, especially at the ladder and diving board where saltwater can wear away at the deck anchors and cause a safety issue. Over time, the salt itself can attack equipment, cement, lighting fixtures, landscaping near the pool and any area of the pool where water evaporates.
Because saltwater pools produce chlorine, some owners have assumed their pool sanitizing needs are met with fewer chemical applications than are required of other types of pools. Saltwater systems actually need chemical treatments about every week. This includes using cyanuric acid to ensure that the salt chlorine generator can reach proper stabilizing levels. If cyanuric acid levels get too high, children, older swimmers, pets, the environment and the pool itself can be harmed. Saltwater pools also require occasional algaecide, clarifier, stain and scale control applications.
Checking the pH and alkalinity balance is an area of pool maintenance many owners fall behind in. This is largely due to some builders and retailers not emphasizing the importance of it. When these levels fall out of balance in a saltwater pool, chlorine effectiveness is reduced, the water turns corrosive and brown stains begin appearing on the pool's surface. Incorrect levels can also destroy the cell in the saltwater generator in less than 90 days. Damage caused by improperly managing the pH balance will not be covered by warranty.
The cell in saltwater generators usually needs to be replaced every 2 to 3 years, costing the owner between $500 (if self-installed) and $800 (when installed by a saltwater pool dealer). The cells require cleaning every 90 days to avoid calcium buildup. If a pool owner goes 6 months without cleaning the cell, its cell life will be shortened, it may break and the pool will take on the appearance of a swamp.
Health and Environmental Concerns
Human skin that is exposed to saltwater systems will absorb sodium, salt and chlorine. Sodium absorption through the skin has been associated with health concerns and higher heart mortality risks, especially among those with high blood pressure, circulatory issues and a history of stroke. Concerns that saltwater systems damage the environment have led to "Ban the Brine" movements, resulting in their use being discontinued in some areas, including Los Angeles County, California.