Rick-

The water in my area tends to be alkaline so I have no experience with
the AN of which you speak

here are some links as a result of a Google search for

Cullneu. water neutralizer

&

culligan water neutralizer

http://forum.doityourself.com/showthread.php?t=199712

this link gives the best discussion but you need to know your mineral
type the media is not cheap if you buy it in small qty

http://ths.gardenweb.com/forums/load...809145387.html

http://www.plumbingstore.com/neutral.

http://www.plumbingstore.com/neutralreplace.html
http://www.plumbingstore.com/neutral.html

sounds like you just replace the used up media with either

calcite (calcium carbonate) or
corosex (magnesium oxide It is food grade magnesium oxide.) or
some mix

the way way to tell if you got the right stuff is to check the pH of
the raw water compared to the treated water, if you've gotten up near 7
you're probably ok



good luck
Bob