Tak-It-EZ Pool & Spa › Guides › Repair
Hard water coats salt cell plates with calcium, and a scaled cell can't make chlorine. Here is how to tell scale from a dying cell.
Salt systems are a good fit for a lot of pools. The cell is a wear part, though, and in hard water it needs regular attention.
The cell makes chlorine by running current across metal plates. That process pushes calcium out of the water and onto the plates. Local water is hard, so a white crust builds up, and a crusted cell can't make chlorine. The control panel shows low output, and the pool starts to slip.
Look inside the cell (with the power off). White, chalky buildup between the plates is scale, and an acid cleaning usually brings the cell back. If the plates are clean and the output is still low, the coating on the plates may be worn out, which means the cell is at the end of its life.
A "no flow" error can be a dirty filter, a closed valve, or a failed flow sensor rather than the cell. Low salt reads the same as a weak cell on some systems. We check all of it before recommending a new cell.
Keep pH from running high, keep calcium from climbing out of range, and inspect the cell every few months. Weekly service includes checking the cell and cleaning it before scale cuts its output.