More and more cities are switching to chloramines instead of chlorine because it saves them money. If your city isn't using chloramines, it is likely that they "GAC"; as it is called, to remove chloramines as well. Chloramine is a different animal and requires Catalytic Coconut Shell Carbon to remove it.
A Commercial-Grade Catalytic Carbon Filter is designed to remove chlorine, chemicals, pesticides and CHLORAMINES, utilizing Catalytic Coconut Shell Granular Activated Carbon
Catalytic carbon is a form of GAC that has been specially treated to change the structure of its' surface which promotes chemical reactions. When water that contains chloramines comes into contact with the catalytic carbon media, the carbon acts as a catalyst which causes the compounds to decompose. The catalytic carbon used in US Water Systems chloramine filter systems is made from coconut shells. Because catalytic carbon is a form of activated carbon, it is also effective at removing chlorine, pesticides, and many organic contaminants
Don't waste your money on just a GAC carbon filter - make sure you get the job done with a Catalytic Carbon Filter. Chloramines do have some toxic effects upon fish, reptiles, amphibians and humans, but chloramines is really detrimental to beer brewing. Unlike chlorine which can be boiled away, chloramines stays in the water under boiling because it is very stable. If you try and brew beer with water containing chloramines, the results will be less than stellar - in fact, they might be downright disgusting!
We offer cartridge type filters for chloramines removal for very light duty applications, but to truly remove the chloramine properly a backwashing tank of catalytic carbon is preferred. As a rule of thumb, your flow rates should be 3-5 GPM for each cubic foot of carbon. If you are unsure what size you need, talk to the Certified Water Specialists at 1-800-608-8792 to find the right filter for your brewing water needs.