QP Model 4000 Dosing Unit: Key Features
- Automatic dosing: provides a continuous, adjustable flow of disinfectant.
- Compatible with chlorine and bromine: works with slow-release trichlor tablets or discs and bromine tablets.
- Manual adjustment: a dial graduated from 0 to 10 for adjusting the dosage level.
- In line installation: It is integrated directly into the pool’s return line.
- 2″ connections: features large-diameter female threaded inlets.
- Bidirectional flow: allows the equipment to be installed in either direction of traffic.
- Prolonged administration of trichloro: moisten only the bottom of the tablets to promote gradual dissolution.
- Bromine operation: It can be used by immersion, keeping the tablets wet to facilitate their dissolution.
- Pressure relief valve: facilitates purging and improves safety during maintenance.
- Opening tool included: helps remove the cap during refilling.
Recommended Pool or Spa Volume
| Product used | Recommended Maximum Volume |
|---|---|
| Slow-dissolving trichloro tablets or discs | Up to 200 m³ |
| Bromine tablets | Up to 95 m³ |
Installation of the Dispenser
The dosing pump must be installed after the filter and before the water returns to the pool. If the system includes a water heater, the dosing device must be installed downstream of it to prevent water with a high concentration of chemicals from damaging it.
The bidirectional design allows the connections to be oriented according to the installation’s needs. To make it easier to open, refill, and maintain the equipment, it is recommended to leave a minimum clearance of approximately 30 cm above and on both sides of the equipment.
It should not be installed directly on copper pipes. It is also recommended to install a corrosion-resistant check valve to prevent gases from flowing back into the filter or heater when the pump is stopped.
Adjusting the Dosage
As a starting point, the manufacturer recommends selecting position 2 when using trichlorine and position 4 when using bromine. The setting should then be adjusted in half-step increments until the desired disinfectant level is reached.
During the first few days of operation, it is advisable to test the water daily. The goal is to maintain a concentration of between 1 and 3 ppm of free chlorine or between 2 and 3 ppm of bromine.
The required adjustment may vary depending on the pool’s volume, water temperature, number of swimmers, and the filtration system’s operating hours.
Compatible Products and Precautions for Use
The QP Model 4000 must be used exclusively with slow-dissolving trichlorine tablets or discs, or with bromine tablets. It is not compatible with multifunction tablets, liquid chlorine, calcium hypochlorite, or fast-dissolving chlorine tablets.
Chlorine and bromine must never be mixed inside the dosing unit. To switch from one product to another, you must completely empty the unit and run it for 24 hours with water and the regulator fully open.
Before opening the cover, turn off the pump and completely release the pressure from the system. Never remove the cover while the equipment is pressurized.
Recommended uses
- Large private swimming pools.
- Condominium pools.
- Facilities that require continuous, adjustable dosing.
- Hydraulic circuits with 2″ return lines.
- Treatments using slow-release trichlor or bromine tablets.


















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