Photochemical Dechlorination of Water Supply for Fish Tanks, with Commercial Water Sterilizers

Abstract

Commercial mercury-lamp water sterilizers can be used for removal of free chlorine in water supplies, by photochemical action. The efficiency of removal decreases with increasing pH, but is little affected by temperature. It is greatest at low initial chlorine concentration. Equipment with either low or high pressure mercury vapor lamps may be used. Removal of 90% of free chlorine can be effected at about 13.0 liters min⁻¹ with a sterilizer using eight low pressure lamps of 40 W, or at 50 liters min⁻¹ or more with two 1200-W sterilizers with high pressure lamps in tandem. Treated water appears to be harmless to fish.