Since 1948, chlorine has been used to sanitize pools. If you went swimming and opened your eyes underwater, you could expect them to sting, your skin to itch and your bathing suit to eventually fall apart from chlorine exposure. Chances are, those with blond hair would be sporting a green tint by the end of summer.
Technology has come a long way since 1948, and now more people – including pool companies and builders – are recommending saltwater pools as an alternative to traditional chlorine pools. Are saltwater pools really that different from traditional chlorine pools? Traditional pools can cause respiratory symptoms including skin and nasal reactions, while saltwater pools are touted as not having those same negative effects.
While the water is equally wet in both types of pools, the feel of the water is different. Saltwater pools tend to feel a bit more luxurious and “softer” to the touch, while traditional chlorine pools feel somewhat “harder.” The best way to illustrate the difference is to think about snapping your fingers under water. In a saltwater pool, since the water is so soft, there is not enough friction between your fingers to snap, whereas in a chlorine pool you can easily snap your fingers underwater.
Saltwater pools were first introduced in Australia in the 1960s, and have recently increased in popularity. It’s the hottest way to cool off to come along in years, and it could make the stinging eyes, itchy skin and bleached bathing suits of chlorine pools a thing of the past.
Here’s a quick chemistry review to recall how the technologies work. Regular chlorinated pools rely on an erosion feeder system. Chlorine pucks are inserted into a floating container or an automatic chlorinator to “erode,” thereby adding chlorine to the water. Some consider the floaters to be a nuisance and the automatic feeders to be dangerous, and then there are hazards in transporting and storing the necessary chemicals. Since chlorine dissemination depends on heat, humidity and pH levels, the hazard of spikes or dilution from a rainstorm requires that you test the chlorine levels regularly and adjust them accordingly. Occasionally, you must also “shock” the pool with larger infusions of chlorine to combat bacterial growth.
Saltwater pools also use chlorine as a disinfectant, but in much lower concentrations. The saltwater system is called a chlorine generator. Unlike an erosion system, the chlorine generator forces salty water across a special electrically charged metal cell. This process separates water molecules into hydrogen and oxygen, and then combines them with salt (sodium chloride) to form sodium hypochlorite (chlorine). This chlorine sterilizes the water. As the saltwater chlorine generator works, the chlorine created is constantly recombining with the sodium, changing back into salts again. The process continuously regenerates once it is started with an initial application of chlorine and salt at the beginning of the season. Generally, saltwater pools need infrequent adjustment. Like a traditional chlorine pool, contaminants and changing Oklahoma weather affect the necessary rate of adjustment.
One of the greatest benefits to choosing a saltwater pool over non-saltwater is that you don’t have to add chlorine directly to the water to keep it clean, thus removing the need to transport and store chlorine. Rather, chlorine is added by way of electrolysis, a method of transforming the saltwater into chlorine gas, keeping the water clear and clean. Since the levels can be finely adjusted, there tends to be less chlorine in the water, which may be why swimmers find swimming in saltwater pools more comfortable.
Water in a saltwater pool is saline, but it’s nothing like swimming in the ocean. Salt concentration in a saltwater pool is similar to the salt content in a human body, but is actually less salty than your tears. Saltwater pools top out around 2,800 to 4,000 parts per million compared to 50,000 ppm in ocean water. You can’t even taste the salt in a well-balanced saltwater pool, with less stinging to the eyes due to the closeness in salinity to that of the human body.
For any pool, the next area of concern is its pH level, which is a gauge of the water’s balance of acid to alkali, and must be checked often in both types of pools. The pH refers to the concentration of hydrogen ions within a solution. If the water is too acidic or too alkaline, it can cause undesirable chemical reactions. If water is too acidic, it will eat away metal equipment, etch into the surface of materials and cause skin pain. However, if the water is too alkaline, it can cause scaling in the plumbing equipment and on the pool’s surface, and can cause the water to be cloudy. With saltwater, pH levels go up fast, so it must be checked more often.
Generally, it is thought that the cost to maintain a saltwater pool is less than the cost of maintaining a traditional chlorine pool; however, the equipment for a saltwater pool has a shorter lifespan and does require maintenance. Instead of buying chlorine tabs, for a saltwater pool you buy salt. You also have to add stabilizer and acid to the saltwater to keep it balanced. Occasionally, you still end up having to “shock” a saltwater pool because the super chlorinate setting on the chlorine generator does not bring the chlorine level in the saltwater pool high enough. Another reason we recommend you check your chemicals daily in the summer months.