Activated charcoal

Activated carbon is highly porous pure carbon. It has a very large surface area for attachment of, for example, gases or dissolved substances from the water. Activated carbon is produced from black coal, brown coal, wood, peat, nut shells or fruit skin of olives and coconuts, by means of suitable carbonisation at about 900 °C. They differ in their cleansing effect and their application.

Algae

Algae are lower plants consisting of a single cell or cell clusters. They can be distinguished by their colours (green algae, red algae, etc.) and their structure (diatom). In swimming pools, it is mostly green algae that develops, which can be cleaned with disinfectants or by adding algicides.

Alkalinity

It corresponds to the carbonate hardness and determines the buffer capacity of water, i.e. how sensitive the water responds to fluctuations of the pH level. It is formed from the carbonates and bicarbonates in the water. If the alkalinity is too low (less than 100 ppm CaCO3), the water tends to frequent fluctuations in the pH level.

Aluminium sulphate

Aluminum sulphate is a white crystalline powder which is used as a soluble flocculant.

Ammonium

Forms in the water as a degradation product of nitrogen-containing organic pollutants (nitrogen degradation). Together with chlorine, ammonium compounds form undesirable chloramines in pool water, the so-called combined chlorine.