dosing pumps for swimming pools

For a standard 50 m³ residential pool, a peristaltic dosing pump is usually the quietest, most economical, and easiest to maintain option if the pipe pressure does not exceed 1.5 bar. However, if you need to inject product against higher back pressure or need adjustable flow rates with high-precision electromagnetic pulses, a diaphragm pump is the better choice.

Consider the following operational differences before deciding what to buy:

• Peristaltic pump: works using rollers that press a flexible Santoprene tube, achieving flow rates of 1.5 to 5 l/h at low pressures; as an example of a panel-mountable replacement, there is the panel-mountable peristaltic pump, 1.5 l/h flow rate.
• Electromagnetic pump: uses a solenoid and Teflon diaphragm to overcome back pressures of up to 10 bar, making it ideal for demanding technical installations.
• Maintenance: the peristaltic pump requires annual replacement of the flexible tube, while the electromagnetic pump requires inspection of the Pyrex ball valves and head purge.

The typical flow rate for dosing pumps used in private pools ranges from 1.5 to 5 liters per hour. To dose pH reducer or increaser in pools of up to 80 m³, a constant flow rate of 1.5 l/h is sufficient to stabilize the levels without causing acidity spikes. For communal pools or continuous dosing of liquid chlorine in pools larger than 100 m³, pumps capable of delivering 5 l/h or more are recommended.

Calculating the right flow rate prevents the pump from being overworked during filtration cycles. If the unit is oversized, it will inject too much chemical before the probe registers the correction; if it is undersized, it won’t compensate for the breakdown of the disinfectant caused by solar radiation.

Every chemical dosing pump requires a set of hydraulic accessories to connect it securely to the filtration circuit. When purchasing your unit, check whether the kit includes the essential suction and discharge components or whether you need to add them separately.

The essential components for a safe installation include:

• Injection valve with a 3/8" or 1/2" thread, fitted with an elastomer check valve to prevent water from the pipe entering the dosing pump.
• Foot valve with a filter and ceramic counterweight, positioned at the bottom of the container to prevent the intake of sediment and suspended solids.
• Flexible transparent PVC suction tubing and rigid, pressure-resistant semi-rigid polyethylene discharge tubing.
• Saddle clamps for drilling 50 or 63 mm PVC pipe to insert the injection point and probes.

Sodium hypochlorite crystallization at the injection nozzle can be prevented by periodically cleaning the insertion point with an acidic descaling solution or warm water. Liquid chlorine reacts with the lime in the pool water right at the contact point, forming calcium carbonate that clogs the outlet and overpressurizes the head.

To carry out this preventive maintenance every two or three months, remove the injector from the saddle clamp and soak it for fifteen minutes in pH reducer diluted with water until the white deposits dissolve. In addition, installing an industrial-grade unit such as the Tekna AKS 603 Standard NHP dosing pump makes priming quick thanks to its manual priming valve, integrated into the PVDF head.

The dosing pump’s electrical connection must be linked to the pool filtration pump motor controls via an auxiliary relay or a socket controlled by the filtration contactor. Never connect the unit to a permanent power outlet without a technical interlock.

If the pump injects pH reducer or liquid chlorine when water is not circulating through the pipes, the concentrated chemical will accumulate in a sealed section of PVC pipe. When filtration resumes, this corrosive pocket will damage seals, sensors, and heat exchangers, and send an irritating cloud into the pool. For maximum reliability in 2026, install a hydraulic flow sensor of the paddle-switch type in series with the dosing pump's power supply.

The Santoprene peristaltic tube should be replaced once per season or every 1,000 hours of continuous operation to prevent mechanical fatigue failures. The constant compression exerted by the rollers causes it to lose elasticity over time, reducing suction capacity and causing corrosive reagent to leak inside the housing.

Replacing this consumable is a quick task that takes less than five minutes: remove the transparent front cover, release the retaining fittings, and install the new tube, lubricating the track with neutral silicone grease. Keeping this replacement up to date protects the gear motor and ensures that the injected flow rate matches the programmed calibration exactly.

The electromagnetic diaphragm pump offers exceptional performance under high back pressure, delivering up to 5 bar of back pressure at flow rates of 8 liters per hour, or up to 12 bar of continuous pressure in adjusted versions. This hydraulic capacity far exceeds the usual 1 to 2 bar in a residential or semi-public pool filtration circuit.

By choosing a robust unit such as the Tekna Evo AKS 800 metering pump, you get a pump head made of PVDF with ceramic balls and a solid PTFE diaphragm, eliminating any risk of leaks or plastic deformation under severe pressure. Its front-mounted potentiometer lets you adjust the pulse frequency between 0% and 100% of the rated flow rate to match the dosage to the exact volume of water.