Maintaning Ca levels with kalkwasser

[ReefDreamz]

I think I would like to begin dosing kalk in my reef. I have the tunze osmolator for top off and I would like to combine it with this tunze calcium dispenser:
http://www.tunze.com/fileadmin/gebra...x5074.8888.pdf

My reef is almost a year old now and so far I have just been doing water changes and dosing with B-Ionic to maintain my Ca and Alk. Usually twice a month (sometimes once) I will do a 20% H2O change, test Ca, Alk, and Mg, and dose B-Ionic accordingly. I cannot complain that this method has not worked. According to my maintenance log my Ca has never tested lower than 390 and always hovers around 400 (I use IO salt but recently switched to RC) which I boost with B-Ionic to 420. My alk has always tested between 3.8 and 4.2 and I have never dosed any of the alk component of the B-Ionic so alk is maintained only from water changes. All tests are Salifert.

I would like to start dosing kalk instead of the B-Ionic because although my corals are healthy they do not seem to be growing. I have zoanthid frags which have not grown at all in over 6 months as well as other LPS. Also the Ca component of my B-Ionic is gone but I do have an unopened jar of kalk.

My main questions are given my previous Ca and Alk experience: Am I a good candidate to dose kalk? Do you see any potential problems? Will the Tunze Ca dispenser work for me? How do I know how much to dose ( I cant control the rate of evaporation so I guess all I can do to control how much I dose is vary the concentration of kalk I use)?
Thanks for any information and advice.
-Cody