Never used it myself...but there have been numerous posts about the results of using it...I'd suggest a search here on the forums and sift through the results...or maybe a member can comment on current useage.
But I still suppliment for calcium and alaklinity plus top-off with kalk to maintain established levels...not the best wayto go about it and it does require time and effort...but its been working for me. Someday I'll need to invest in a calcium reactor myself....