PURA Chlor-Lock 1 lb. Treats 25,000 gal. **** PRODUCT INFORMATION **** **** PRODUCT MANUAL **** PÛRA ChlorLock is the safest and most effective way of neutralizing chlorine and bleach in all fresh and salt-water aquarium applications. It also the most cost effective way of preparing aquarium and pond water. 1 lb. Treats 25,000 gal.