Nonetheless, there are areas where the water is hard, or has a high mineral content, which can lead to scale. Some filters allow debris to pass through the cell, and it sometimes lodges between the plates in the cell. In all of these cases, the self-cleaning feature may not be adequate, and manual cleaning is necessary.
If it is determined that there is excessive scale formation between the plates or, if debris is present, the cell may be cleaned using the high-pressure jet from a garden hose. If the cell can not be can not be reasonably cleaned with this technique, it should acid-cleaned. To acid clean the cell, turn off the power to the unit, either by switching off the filter pump or setting the circuit breaker to off. Mix one quart of muriatic acid, with one gallon of water in a plastic bucket. Always add acid to water, never the reverse.
The equipment manufacturer Pentair Water Pool and spa offers an electrolytic cell acid cleaning kit for their popular Intellichlor chlorine generators. The kit includes an O-ring, a washer, and a cap to allow acid to be poured into the electrolytic cell plates for cleaning. It also serves to protect the sensitive areas of the cell during washing. Remove the unit from the pool‘s plumbing system by unscrewing both unions from the unit. Placing the O-ring in the washer, and the washer in the cap, screw the cap on the Intellichlor unit.
Place the cell vertically in a five-gallon bucket with the cap end down. Pour the acid solution into the cell until the blades are just covered. Allow the acid solution to bubble to clean the blades. The acid should only be contained in the cell and not around it. The bubbling is caused by the scale, which is calcium carbonate, being dissolved from the plates, if rigorous foaming action does not begin, the cell does not need to be cleaned. Otherwise, allow the cell to remain in the solution until the foaming has stopped. It is not recommended to leave in acid in the cell for more than 30 minutes because excessive acid washing will damage the cell.
Remove the cell from the bucket and place in an empty five-gallon bucket. Rinse the cell thoroughly with clean tap water and inspect for remaining deposits. If visible deposits are present, immerse the cell again in the solution for further cleaning. Additional acid may need to be added to the solution. Rinse the cell again with clean tap water and inspect. If the cell appears to be clean, remove the cap, o-ring, and washer, which can be used for future use. Replace the cell and resume normal operation. If this acid washing procedure is necessary, it is recommended that a sample of pool water be analyzed for excessive hardness or improper water balance. Excessive calcium levels cause scale and should be monitored or frequent cell cleaning will be necessary.
On the other hand, if no scale or debris deposits have been observed in the cell after two bimonthly inspections, it may not be necessary to continue these bimonthly inspections. Nonetheless, it is still a good idea to remove the cell for inspection at least twice a year because of possible changes in pool water chemistry and filtering effectiveness.