You can go online at Costco.com and apply for a Costco Membership there by adding it to your shopping cart if you are shopping for the first time. Your membership card will be mailed to you within 7-10 days but you can actually shop at the online store immediately.
The three most common chlorine-containing substances used in water treatment are chlorine gas, sodium hypochlorite, and calcium hypochlorite.
A number of technologies are now available to reduce the levels of chloramines in water. use of ozone gas, ultraviolet light irradiation, and the addition of non-chlorine oxidising chemicals to the water. The use of these technologies should be considered for indoor aquatic facilities with significant bather numbers.