Dropson decalcifier in recirculation, anti-scale solution for water tanks and wells

Dropson, solución antical para aljibes

The water tanks used for domestic water supply are often supplied with well water, with a very high degree of hardness. The installation of the Dropson decalcifier in recirculation allows large quantities of water to be treated in these cases under extremely hard conditions and provides much higher peak flow rates.


Case of extreme hardness: well + water tank

The well water is stored in a tank for later supply. These waters are usually very hard and may contain microorganisms and chemicals attributed to natural geological factors or human activities.

Together with other particles and sediments, limescale can damage domestic hot water production systems and cause damage to the rest of the installation.

This type of installation requires an anti-scale system in the recirculation of the supply tank to protect the tank and the DHW circuits.

It should be remembered that the anti-scale treatment does not replace the chlorination systems used to disinfect and purify the water. A stand-alone system such as a metering pump is recommended for this purpose.


Dropson recirculating softener

In cases of water recirculation such as the one explained above, it is important to pay attention to the installation diagram of the Dropson water softener to guarantee its maximum performance. Get to know the different parts of such an installation with this infographics:

Esquema de instalación Dropson en recirculación

1. Water inlet

Before entering the tank, the water must pass through a 100 micron sediment filter that retains the soil particles and coarse suspended sediments, especially if it is well water.

The tank will be filled to its maximum level, indicated by the buoy or float.


2. Recirculation

In order to recirculate the water inside the tank, a second circuit must be available consisting of a sediment filter, a low consumption recirculation pump and an anti-limescale system such as the Dropson water softener.

  • It is necessary to install a sediment filter (50 microns) prior to the pump and the Dropson system. This filter retains finer particles than the previous one to prevent clogging of the installation and improves the performance of both the pump and the Dropson limescale remover.
  • As it is a closed circuit, it is necessary to install a recirculation pump that moves the water throughout the circuit. Its flow rate must be equivalent to that of the selected Dropson system. A timer can be integrated to program the automatic running hours of the pump.
  • After the filter and the recirculation pump, the water passes through the Dropson water softener and returns to the tank once it has been treated. Dropson crystallizes the limescale and prevents it from becoming embedded in the facilities.


3. Water outlet

A 25 micron sediment filter installed at the tank outlet filters out any impurities that may remain in the water once recirculated and before it enters in our home.

For a first use, it is advisable to recirculate the water a minimum of 3-4 times the total capacity of the tank.



  • The main advantage of installing a Dropson water softener in the recirculation of a water tank is that we can treat cases of extremely hard water.
  • Dropson also allows you to treat large amounts of water without requiring the installation of a high flow rate model.
  • This type of application also offers a water outlet with a very high peak flow rate, suitable for certain applications such as irrigation.


What a minimum flow rate do I need?

To determine the minimum peak flow rate of the recirculation circuit, the maximum capacity of the tank must be taken into account. The minimum peak flow can be calculated as follows:

Cálculo de caudal para instalación en recirculación

Practical example:

For a 50 m³ tank, a minimum flow of 12 m³/h would be required and we would install the corresponding Dropson anti-scale system.

In those cases in which the tank capacity exceeds, 50 m³ the calculation may vary, so it is recommended to request a personalised study.