Swimming is great exercise, but the effect of chlorinated water on your skin and your eyes may keep you out of the water more than you'd prefer. This is one reason many pool owners choose the saltwater option, and making the conversion is easier than you might think. All you basically need to do is to install a chlorinator in line with the pool plumbing, balance the pool chemicals, add salt to the water and turn on the chlorinator. The most important part of the process is to choose a chlorine generator that can easily handle the volume of water in your pool. An undersized generator won't produce enough chlorine and will wear out quickly.
Saltwater Chlorination Basics
Chlorine is the sanitizer in saltwater pools, but instead of adding it directly to the water, you add salt, and the chlorinator converts it into chlorine through an electrolytic process. The cells in the chlorinator separate sodium chloride into sodium and chlorine ions, and they in turn form hypochlorous acid (HClO) and sodium hypochlorite, which are the two main sanitizers in conventional chlorine pools.
The pool water is not as salty as seawater. In fact, the recommended salt concentration of 3,000 parts per million makes the water only one-tenth as salty as seawater, or about as salty as saline eye drops. Swimming in such a mild saline solution is pleasant and soothing, but salt tends to make the water alkaline, so it's important to monitor the pH frequently and take steps to lower it when necessary, or the chlorine produced by the generator will be ineffective. Moreover, the salt cells tend to build scale and must be cleaned often and replaced every three to seven years.
Sizing the Chlorinator
Once you've decided to convert to a saltwater pool, you should choose a chlorinator rated for a pool with about a third more water than yours contains. That way, you can run it at a moderate setting and be sure the chlorine output is sufficient to keep your pool clean. To calculate the volume of your pool, measure its surface area in feet and multiply that by the average depth in feet. Multiply these numbers to get the volume in cubic feet, and then multiply that result by 7.5 to convert to gallons.
Installing the Chlorinator
Installing a saltwater chlorinator involves two steps. The first is to install the control panel, and the second is to install the salt cell itself. Place the cell into the pool's circulation line downstream from the filter, heater and circulation pump. Installing it is a matter of cutting out a section of pipe and replacing it with the cell, which has fittings on both ends to glue onto the pipes. Check the arrows on the cell to be sure they are pointing in the direction of the water flow before you glue it in.
Installation of the control panel is a bit more complicated. It comes with detailed instructions for installation, but if you aren't comfortable working with electricity, you'll probably want to hire a pro to do this part. The panel should be installed a minimum of 5 feet away from the pool and as close to the pump timer as possible. The best place for it is on a wall or similar flat, vertical surface in a location that allows easy access on all four sides.
Starting Up the Generator
Before you turn on the chlorine generator, it's important to balance the pool chemicals. The pH should be between 7.2 and 7.6, and the total alkalinity between 80 and 120 ppm. You should also check the phosphate level and add a phosphate reducing chemical if the reading is higher than 125 parts per billion. Phosphates contribute to scale formation on the salt cell. Finally, add enough cyanuric acid to bring the concentration to between 50 and 75 ppm. Cyanuric acid is a stabilizer that prevents chlorine from being degraded by sunlight. Some pool maintenance pros recommend shocking the pool with a standard chlorine shocking chemical and allowing the free chlorine level to fall below 5 ppm before starting the salt generator.
The final step is to add salt, and regular table salt is best. The manual will tell you how much to add, based on the volume of the pool. Do this with the pool pump turned on and the salt generator off. Mix in the salt; allow it to circulate, and then take a measurement and add more if the level is below 3,000 ppm. When you're done, the salt concentration should be between 3,000 and 3,500 parts per million.
Once your chlorinator is operational, you won't have to add chlorine, but you will have to maintain the salt level. Take regular chlorine readings, and set the output of the chlorinator higher when the level falls below 1 ppm. You should also maintain the balance of pH, alkalinity and other chemicals just as you would in a regular pool.