Electrochemically activated water (ECA-water) is a term for salt water through which a current is passed. As a result, it is enriched with stable (at pH 8.5) active substances which destroy the cell membranes of bacteria and fungi but do not leave residues. ECA-water is diluted and used at concentrations of 2-10 ppm of active chlorine. Therefore, the EC of the water increases slightly with 0.1 mS/cm, so care should be taken when applied to vulnerable plants such as young cucumber plants. ECA-water is effective against Pythium, crazy roots, Botrytis, clogged drippers (bio film) and algae deposits on pots and watering mats and avoids a lot of work and use of chemical disinfectants. The stable ECA-water can be kept in a tank to be dispensed into the mixing water at a concentration of 8 ppm. In horticulture, 2 litres of ECA-water are generally used per 1 000 litres of nutrient solution. It is important to prevent a build-up of polluting particles. Once the pipes are clean, a constant dosage can be used. When a number of algae suddenly increases, the dose should not be raised because the bio film must only gradually dissolve to prevent sludge formation. The unit capacity should be determined by the peak consumption: 176 to 4 400 litres of ECA-water can be made daily, which is sufficient to treat 88 000 to 2.2 million litres of irrigation water per day. A device costs € 17 000 and the production of one litre of ECA-water (KCl salt, water, electricity, replacement cell) costs € 0.047. The maintenance and energy consumption are hence negligible compared to other techniques.