Inspect Cell light on a Hayward AquaRite
Flashing, the unit is still running and asking to be looked at. Steady, cell efficiency is greatly reduced and it has stopped producing chlorine. The 500 hour figure attached to this light is a resettable reminder interval, not a cell lifespan.
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Inspect Cell
INSPECT CELL A flashing indicator signifies that either the cell efficiency is reduced or that it is time for regularly scheduled cell inspection. In either case, inspect cell and clean if necessary. When illuminated steady, cell efficiency is greatly reduced and the AquaRite has stopped producing chlorine. Inspect, clean or replace if necessary.
Hayward AquaRite owner's manual, 092540 RevG
Flashing or steady? They are not the same
Flashing: still running. This state is a warning, not a shutdown. Steady: stopped. That is the state worth acting on. The numeric trip point for this state has not been checked yet.
A different light?
Then what
Two outcomes from here. If the reading came back fine and the light is still on, you are probably looking at scale rather than a dead cell, and cleaning costs almost nothing. If chlorine still does not recover after the salt is right and the cell has been cleaned, the plates are the problem and no amount of cleaning brings a worn coating back.
The sixty second test, before you spend anything
The controller's salt reading is a calculation, not a measurement. It is derived from how the cell is behaving, so a tired cell, cold water or low flow all move it. That is why the first real step is measuring the water yourself and comparing the two numbers.
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Take the sample from elbow depth, away from the returns
Surface water and water sitting in front of a return jet are not representative. Elbow depth, mid-pool, in a clean container.
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Measure it with something that is not the controller
A salt test strip or a drop test kit both give you an independent number. The point is only that the second reading does not come from the same box you are trying to judge.
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Compare it against what Hayward AquaRite says the level should be
The ideal salt level is between 2700-3400 ppm (parts per million) with 3200 ppm being optimal.
Hayward AquaRite owner's manual, checked 2026-07-25
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Read the two numbers together
Water low and display low, in agreement, means the pool needs salt and the cell is reporting correctly. Water in range while the display reads low is the interesting case: the water is fine and the box is wrong about it, which points at the cell, the flow or the temperature rather than at your salt level. This controller's own published trip point is 2700 ppm, so a display reading under that with correct water is the reading worth acting on.
Adding salt on the strength of a controller reading alone is the most common way owners spend money in this category before they need to. Salt does not evaporate. If the water tests in range, the pool does not need any.