I use kalkwasser for all top off, and evap quite a bit through the course of a day... and being that my tank's still kinda new and lotsa my corals are frag-sized/small, I actually tend to have trouble keeping the numbers within the norm (I know, not what you wanted to hear ;-). I used B-Ionic for a while, and while I really liked it, found I was using quite a bit, and the daily regime was too much for my husbandry habits. Since switching to Kalkwasser I've noticed my Alk go through the roof, and it takes the Ca with it.. When things are rocking, my alk runs 10-12 dKH, Ca's up around 600 ppm...
I'd suggest giving Kalkwasser a try at least. I know it can be a pain to mix up, decant, dose, etc... and getting a Reactor setup like I run can be expensive (Dosing pump's the biggest part - the Rxr itself can be made for under 10 bucks)... but it's been really great for me. Everything grows nice and fast (although not as fast as under the B-Ionic for some reason), cheaper than anything, and it's easy to use/hard to screw up. I've dosed over a Liter of Kalk into my system before, and not noticed any ill effects. I'm not suggesting this as a regular treatment, but more as a way of waylaying any fears you might have.
- Mac