Algae are micro-organisms that construct organic substances from inorganic substances, carbon dioxide and water.
The propagation and proliferation of algae occurs via spores that are spread everywhere together with dust in the air, causing them to enter all swimming pools, even covered or indoor swimming pools. Managing the composition of water is intended to keep the content of organic contamination as low as possible. Algae formation as a source of organic contamination must therefore be avoided as far as possible. The growth of algae is easy to prevent by regularly (e.g. once a week) giving the pool water a chlorine shock. Calcium granulate is an excellent agent for this purpose.