I have dosed kalk with mine for six months or so. Works great. I have heard you should run vinegar through it every now and then but I haven't bothered. Two part should be far easier on the pump I would think.
Even if I have to replace it once a year it is still a hell of a deal.
<a href=showthread.php?s=&postid=10500922#post10500922 target=_blank>Originally posted</a> by raynist BTW, you can find these cheaper at marine depot or other places. I usually see them for $11 or under.
Check out other places. I got mines from MD for ~11 bucks. I use mines as a ATO and the flow slows down after a while (just RO/DI water, no Kalk) to a steady rate. To increase flow, I unplug the silicon tube going to it for a few seconds and then plug it back in. Flow increases for a while again til it settles down. I haven't had time to look into it or run vinegar thru it yet.