In a salt chlorinator, the electrode (cell) generates the chlorine. Over time scale builds up on the plates and cuts its output. Many units have self-cleaning by polarity reversal, but you should still check the cell 1–2 times per season (and clean it if you see a white crust).

How to clean it

  1. Turn the system off and close the valves to prevent air getting in or water getting out.
  2. Remove the electrode following your unit's manual.
  3. Try pressurized water first, without scraping or using anything that could damage the metal plates.
  4. If scale remains, in a well-ventilated area prepare a container with 1 part pH reducer (acid) to 5 parts water (add the acid to the water, never the other way around).
  5. Submerge only the metal parts for about 4 minutes; bubbling is normal.
  6. Rinse well (you can do it in the pool) and reassemble.

Safety

  • It gives off toxic, corrosive fumes: don't breathe near it and work outdoors.
  • Wear rubber/vinyl gloves and old clothes (a drop of acid burns a hole in fabric).
  • If you pour the liquid into the pool, watch that the pH doesn't crash.