Estimate needed chlorine output and SWG runtime.
A salt water chlorine generator should be sized to produce enough chlorine for the pool during hot weather, heavy sun, and normal swimmer use without forcing the cell to operate at maximum output every day. Choosing a larger cell usually provides more flexibility, shorter operating time, and better performance during high chlorine demand.
The gallon rating printed on a salt system is usually based on ideal operating conditions. Real pools may have stronger sunlight, warmer water, higher bather loads, or longer swimming seasons. A cell rated exactly at the pool’s volume may need to run close to 100% for long periods.
Many pool owners prefer a cell rated for about twice the actual pool volume. For example, an 18,000-gallon pool is often easier to manage with a cell rated near 40,000 gallons rather than one rated near 20,000 gallons.
A salt cell only produces chlorine while water is flowing and the unit is energized. If the pump runs fewer hours, the output percentage must usually be higher. A larger cell can often meet the same chlorine demand at a lower percentage setting.
If the required output percentage is above 100%, the current cell and runtime cannot meet the estimated daily chlorine demand. Increasing pump runtime may help, but a larger cell may be the better long-term solution.