Chlorine
Water supply companies from time to time add chlorine to their supply lines for disinfection purposes. Ornamental fish and other aquarium occupants cannot tolerate chlorine, even in very small quantities, and it needs to be taken out of the water before it is added to the aquarium.
AQUAVITAL CONDITIONER+ neutralizes chlorine in a few seconds very effectively.
Chlorine can also be expelled from the water by intensive aeration with an air pump or filtered out using AQUAVITAL CARBON.