Actually as the media in a ca reactor dissolves mg, trace elements, and whatever else is in the media is liberated. I'm sleepy, maybe someone else can elaborate further. (Greg, where are you now????)
Ca reactors are expensive and can be touchy to dial in initially. Once set up they require very little maintence and have few drawbacks.
Kalk, and Kalk reactors are also great, but if misused can cause large PH swings. Also dosing Kalk without a Kalk reactor can be another chore to deal with and if not mixed and added correctly it can actually throw off ca/alk levels or even make them crash.
As for all the kent additives, just do regular water changes and throw all the additives you can't test for in the trash or place them on a dedicated shelf for decoration since they aren't good for much (most of us have a shelf, box or or other round file area full of kent and other brand additives and miracle cures.) No offense intended here, there are a ton of products on the market that make big claims but have very limited effectiveness. Lots of the additives out there actually have short shelf lives but generally don't have a mfg date listed. Also if there isn't a good test for something there is no way of knowing if your dosing right. Put your time and energy into regular water changes and your much better off.
As for Ca / Alk maintence, Ca and Kalk reactors may seem expensive but if your attempting to keep even vaugely steady levels you'll save quite a bit just in testing supplies. Try testing Ca and alk levels daily, at the same time of day, for a week straight. you'll probablly see what I mean. As for your specific tank (all LPS), the Ca and Alk needs probablly aren't super high, but personally IMO keeping Ca and Alk steady does a lot for general tank stability and control of problem algae and whatnot.
.02$
jk
