Salt Cell Reading Low or Making No Chlorine?

A salt system that is reading low, flashing inspect cell, or simply not holding chlorine is usually not a dead cell. In Arlington the most common cause by far is scale on the cell plates — and that is something you can often deal with yourself.

Test the actual salt level, not the panel

The panel reading is inferred, not measured, and a scaled or ageing cell reports low salt when the salt is fine. Before adding a single bag, test the water with strips or take a sample in for a proper reading.

Adding salt on the strength of a bad panel reading is how pools end up well over range, and the only fix for that is draining and replacing water.

Cause 1: a scaled cell

North Texas water is hard, and calcium plates out onto the cell as it runs. A scaled cell cannot produce chlorine properly and cannot read salt accurately either, which is why the two symptoms arrive together.

How to tell

Shut the system down and take the cell out. Look through it end to end. Clean plates look like dark, evenly spaced blades. A scaled cell has white crusty deposits bridging between them, sometimes enough to close the gap entirely.

Cleaning it

Light scale often comes off with a strong hose jet. Heavier deposits need a proper acid soak in a dilute solution, always acid into water and never the other way round, and only for as long as it takes to stop fizzing. Over-soaking strips the coating off the plates and shortens the life of an expensive part — which is why many people would rather we did it.

Cause 2: the water is simply too cold

Salt cells stop producing below roughly 60°F, and output falls off well before that. Our winters are mild enough that people expect year-round production, but water temperature still drops under the threshold for weeks at a time.

If output faded as the weather turned and the cell looks clean, nothing is broken. Plan on supplementing chlorine through the coldest stretch rather than chasing a fault.

Cause 3: the cell has reached the end of its life

Cells are consumable. The coating on the plates is used up by normal operation, and three to seven years is the usual range depending on run hours and how well the water has been balanced.

If the cell is in that age bracket, looks clean after a proper wash, and still will not produce or still reads low, it has most likely reached the end rather than developed a fault.

Cause 4: not enough flow

Salt systems have a flow switch and will not energize the cell without adequate flow — the same protective logic a heater uses. A blinded filter, a packed basket or a pump that is not moving water properly will show up as no chlorine production.

If the filter is the restriction, see pool filter pressure too high. If the pump is the problem, start with a pump that will not prime.

Cause 5: stabilizer is too low

This one fools people constantly. The cell can be producing perfectly while the chlorine disappears, because without enough cyanuric acid the Texas sun destroys it almost as fast as it is made.

If the cell is clean, the salt is in range and the system reports normal operation but you never hold a reading, test CYA before condemning any hardware.

What it costs in Arlington

Cleaning a cell is a small job. Replacing one is a real part and worth confirming properly before you buy, which is exactly why it is worth having it tested rather than guessing from the panel. Flow faults usually turn out to be filter or pump work instead.

Our service call is $149, it covers the full diagnosis, and it comes off the repair price if you go ahead. Every repair carries a one-year warranty. See pool equipment repair for salt systems, filters and automation.

Making a cell last

Keep calcium hardness and pH in range, because scale is the thing that kills cells here. Inspect it a couple of times a year rather than waiting for a warning light. Do not over-clean it, and never leave it soaking longer than it needs. Run the pump long enough to make a full day of chlorine in fewer hours rather than running a worn cell around the clock.

Pool Pros — Family-owned pool service in Arlington, TX since 2005. Call 682-399-2593 for a free estimate.