What is a Salt Water Pool? A salt water pool is a pool that uses salt in the water to generate chlorine. It is simply a pool that uses a chlorine generator, which through the process of water passing through an electronic cell, produces sodium hypochorite or liquid chlorine. So, a salt-water pool is NOT a chlorine free pool. It is a pool that makes its own chlorine.
How salty is the water? Most chlorine generators require salt content of 3000 – 4000ppm (parts per million). Ocean water has a salt content of around 35,000ppm. The average person cannot taste the salt in a salt water pool since the salinity is so mild. In a salt water pool the salinity is close to that of the human skin so the water feels smooth, and your skin feels smooth upon getting out of the pool.
How does a Salt Water Pool System work? The chlorine generator system consists of a control unit and a salt cell. The control unit regulates how long the power is supplied to the salt cell. Chlorine is produced when power is supplied to the cell. Typically, there is a control knob on the unit to regulate the amount of power going to the cell. By turning the control knob up the unit supplies electric to the salt cell for a longer amount of time. Salty water flows through the cell (with the pump on) and through the process of electrolysis, the salt in the water is converted into liquid chlorine.
What are the benefits to a salt water system?
How often do I have to add salt? Salt in the pool is only lost when water leaves the pool through backwashing, splash-out, leaks, or vacuuming to waste. Most pool owners with salt water need to replace about 10% of their salt during each season.
What system maintenance is required? You will need to monitor and keep the salt concentration between 3000 to 4000ppm to have an adequate amount of salt for the cell to produce the chlorine necessary to maintain the pool. Salt test strips and kits can be purchased at your local pool supply store. Most controls will display the salt content on the LED panel on the control. Your control knob may also have to be adjusted, up or down, as required to keep the chlorine production in line with the demand. Since the chlorine generator will only make chlorine when the pump is running you need to have the pump on when demand is highest. Typically setting your timer to run during the daylight hours from about 8am to 6pm daily in the summer is about right. Through a bit of trial and error you will find the control setting and filtration time you need to meet the chlorine demand during different points in your swimming season. Occasionally, if the chlorine reading is below recommended levels you may need to super chlorinate the pool manually to supplement the chlorine feed in order to raise the chlorine level quickly.
What maintenance of the cell is required? Most units have a self cleaning feature built right in that reverses the polarity of the voltage through the cell to clean off scale buildup off of the cell plates. If the unit does not have a self cleaning feature, at the end of the season, a mild muriatic solution may be used to clean the cell of 10 parts water to 1 part muriatic acid.
Where does the salt go? The salt is poured directly into the deep end of your pool. Using your telepole and brush head, brush any that is lying on the floor of the pool until it is fully dissolved.
Do I still need other chemicals? Yes! The salt system generates chlorine only. Chlorine is most effective and your pool healthiest for swimmers and equipment with properly balanced water. Alkalinity, pH, Calcium, Cyanuric Acid levels will still need to be maintained at proper levels. (See for Guide to Water Care article).
What size chlorine generator should I purchase? Salt systems produce a certain amount of chlorine per hour. You will need to consult with your pool professional to purchase the system that will keep up with the chlorine demand for the volume (gallons) of water in your pool. Manufacturer specifications will indicate the number of gallons of pool water for each model system. If your pool volume is between 2 models buy the larger system.
Is there a cost benefit to using a chlorine generator? Most pool owners purchase salt systems for improved water quality, swimmer comfort and the other benefits discussed above. Nonetheless, you will save a good bit of money by no longer needing to purchase chlorine. After the upfront cost, it usually takes about 2 to 3 years for the system to pay for itself.
Why do swimmers who consider themselves “sensitive” to chlorine not experience sensitivity in salt water pools? Many times the people who have sensitivity or “allergic reactions” are not actually having a reaction to the chlorine. Packaged pool chemicals have additives and by-products that don’t exist in the chlorine generated by the salt cell.