Neutral units are dolomite filters used to increase water hardness and/or pH. The channelling created by water on the filter media shall be periodically removed with a backwash. The backwash frequency can be programmed by time. The system is to be sized according to the flow rate required by the user.

Neutral units are made up of:

• head with hydropneumatic valve in plastic material and electronic timer ET 500 F

• cylinder in plastic material covered in fireglass containing the active media of calcium carbonated (dolomite).