Water Filtration is extremely if you live in an area that Chlorinates thier water. Chlorine is extremely harmful to your koi, and removal is necessary. At the turn of the century it was realized that adding chlorine gas as a disinfectant to drinking water reduced the incidence of waterborne disease in humans. Chlorine continues to be used as a disinfectant in water mains and koi keepers need to be aware of it's harmful effects.

Ensure your water is free of chlorine and other harmful contaminants by filtering your water