A composition containing alkali carbonate peroxyhydrates and alkali hydrogencarbonates isclaimed in which the alkali carbonate peroxyhydrates are contained in aquantity of more than 0 upto 85 % weight relative to the total amount of the composition and that issuitable for combatingthread algae and germs and parasites in water and in bodies of water. Thecomposition, in contrastto alkali carbonate peroxyhydrates as a pure substance, can be stored andtransported well andhas no longer an oxidizing effect.
