How To Clean A Salt Water Cell
One of the biggest limitations of salt water systems is the regular cleaning required of the cell. The cell has metal plates inside which are polarized and much like a car battery these will develop scale buildup on them. The damage from scale as well as the time period required in between cleanings of the cell will depend on how well you balance your water chemistry, the amount of calcium hardness in your water as well as the quality of electrode produced by the manufacturer of your salt water chlorinator.
As this scale develops it will prevent the ability of chlorine generation. The electrodes would typically send a small electric current between the plates which causes electrolysis and separates the chlorine from the sodium. AS the scale builds over the electrodes the amount of current being sent into the water will reduce more and more resulting in lower measurable levels of free chlorine in your water.
Another important function of the scale buildup is heat damage. As part of the electrolysis process there is a small amount of heat that is generated. As the scale grows the heat generated by the electrode plates gets trapped and can not disperse into the water. This heat damage also causes the cell to produce less chlorine as the metal that the electrode is made from loses its ability to conduct electricity. A scale problem left unchecked will ultimately result in a failed generation cell and would require replacement.
The scale that builds up on the electrodes actually has a pH that is very damaging to metal components so prolonged periods of time with scale on the electrodes can cause failure.
To prevent this problem from developing you should inspect and potentially clean the cell every 500 hours of operation. Many salt water chlorination systems have a timer built in to them that will advise you to inspect the cell every 500 hours. At this point you would shut off your circulation system and remove the cell from the plumbing lines. By looking down into the cell you can see the metal electrode plates on the inside. A clean cell should be just that, clean, in that there is zero scale buildup visible on the electrodes. Even moderate scale buildup can cause the cell to function poorly so be sure to clean the cell if any scaling is noted.
The actual cleaning of the cell only takes 20-30 minutes using a cell cleaning solution. You can purchase cell cleaning solution from most swimming pool and hot tub stores or you can also make your own. To clean a salt water cell simply immerse the entire cell in a acid mixture of 1 part muriatic acid to 4-5 parts water for 20-30 minutes. The cell should bubble when immersed in the water. After cleaning in this solution be sure to rinse very well to remove any acid from the components before reinstalling.
With proper chemical maintenance in your pool or spa you can often get away with only cleaning the cell one time per season. If you have hard water or are not very good with your chemical balance then you should inspect and potentially clean the cell more often than this. Also inspect your cell any time you notice a change in the amount of chlorine in your pool as this will be one of the first indications that the cell is not functioning properly.