"Tim Zimmer" wrote in message
news:1116159869.def3c9c864daf397232f7c2e7c0c35e8@b ubbanews...
Our ionizer drinking water filter needs changing once every 8
month or more if the city water is clean. Since our city is pretty
clean I only worry about chlorine. How can I tell if the activated
charcoal filter is still working properly?



You may want to look into getting a TDS (total disolved solids)
meter. It will tell you beyond a doubt when your filters aren't
pulling their weight anymore.

billy