Ca Reactor w/ or w/o Kalk

My reactor will be in next week and I'm really wanting to get away from dripping kalk.  I decided to go with a GEO reactor which is a single stage unit so I'm not sure how it is going to effect my PH.  Other than PH is there any benefit to dripping kalk with the reactor?  Is anyone running a single stage reactor w/o kalk?

Also, do calcium reactors also provide magnesium? or is mag something I still need to keep an eye on? 

Any thoughts would be appreciated,

Calcium reactors do indeed supply magnesium.  Think about where all your magnesium is going?  Coralline and sps/lps growth right?  What's in your calcium reactor?  Ground up coral.  So a calcium reactor will actually provide magnesium in the same proportion as your sps in your tank are consuming it (because everything in the reactor dissolves).  But, you'll never see your magnesium climb from the use of a reactor as coral is only like 1% magnesium.  But if your magnesium depletion is due mainly to SPS growth, it should maintain it ok.

BTW, reactors also supply strontium and if a bad substrate is used can also add phosphate.

Travis, I think pH is the only reason to dose kalk in tandam with a calcium reactor.

Thanks guys, the both articles are very informative . 

Well it arrived today bad thing is I'm in Colorado so I can't play with it until this weekend...

Marcus, every thing you see in the picture cost 705.13 delivered.  About the only thing missing is some calibration liquid for the PH controller and a second brass check valve.  The brass check valve is optional but to me it's just extra protection.

Thanks Jon, I'll keep everyone posted on its performance.  I think a dual chamber would have been nice but I've heard a lot of good reports from this unit.