Amperometric regulation

for salt water pools

Amperometric regulation indicates the amount of free chlorine in the water.

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Amperometric regulation

Free chlorine – or hypochlorous acid – has an almost magical effect, as it makes the water potable.
In 1930, its use in the New York water supply even succeeded in eradicating typhoid!
However, even if chlorine is an excellent disinfectant, it is better not to overdose it.

In all pools, dosing chlorine is often seen as a balancing act.
If there isn’t enough, bacteria, micro-algae and micro-organisms invade the pool.
If there is too much, the smell of chlorine pervades the pool and swimmers get itchy, sore eyes.

This is why pool maintenance specialists have created a regulation system to handle chlorine: amperometric regulation.

Stérilor water treatment solutions


What is amperometric regulation?

While the difference in the Redox measurement offers a preview of the disinfectant power of the pool overall, the amperometric sensor indicates the level of free chlorine in the pool water.

This measurement is less sensitive to water parameters and the free chlorine value is directly indicated on the appliance screen.

For sheltered or indoor pools, the risk of over-chlorination is higher.
You should always plan to invest in a chlorine regulation system when buying your covered swimming pool.


How does an amperometric regulation system work?

Chlorine is measured in a specific analysis chamber.
In most cases, it is located after a sequence of other analysis chambers.
Upstream of the chlorine measurement, these tests take into account factors that may impact calculations (pH, temperature) while guaranteeing optimal operation of the regulation system (flow, salt level).

Once the appropriate quantity of chlorine is determined, the regulation is done in relation to specified set points: a dosing pump injects an amount of liquid chlorine and the electrolysis production cycle is modulated.
The accuracy of the system due to specific measurements of chlorine enables it to rapidly respond instead of applying random corrective actions.
The risk of drift is considerably limited: the disinfection process automatically and continuously adapts to the actual needs of the pool.
The water quality remains optimal, even in the event of brutal variations, such as a sharp influx of users for example.

Caution: stabiliser products can falsify the readings on the amperometric sensor.
As the regulator will itself stabilise the level of free chlorine in the water, these products will no longer be of use.


Manual chlorine test

Although the amperometric regulator greatly facilitates day-to-day water management, Stérilor recommends a second chlorine measurement at least once a week, to be on the safe side.
This verifies that the level read by the amperometric regulator sensor remains correct.

If this is not the case, it should be dipped in a reference solution to readjust it to the correct chlorine level.

Like for any pool water test, the filtration system must have been operating for at least 30 minutes and the water sample must be taken at around 30 cm below the surface (half a forearm).

The three types of analysis are:

  1. Chlorine test strips

The test strip is dipped in the pool water like in a pH test.
After a few seconds laid flat, the colours of the strip are compared with the manufacturer’s information to reveal the chlorine level.


  1. Chlorine droplet test

In this test, the pool water is mixed with a few drops of liquid reagent.
The sample will change colour and this colour must be compared with those shown on the manufacturer’s documentation.


  1. Electronic tester

The electronic tester is extremely easy to use.
It is first dipped in a reference solution then the sensor is dipped in the pool water.
The chlorine level is displayed on the screen.
The tester must be calibrated with a reference solution.


Learn more about our amperometric regulators