Why should I do anything that is logical and simple?  Good idea!  Thanks Jon!

Fred

In a Kalk Reactor, does the ALK always stay the same? 

Yes, they are designed to dose a saturated solution.

Is the clear Wasser the same ALK as the lime slurry? 

No, clear kalkwasser is water that is saturated with Ca(OH)2.  The slurry solution is just the clear kalkwasser with particles of undisolved lime or CaCO3.  As such, the slurry is a bit more "potent".

How does one know what to expect the ALK to be on the output of the DYI kalk reactor?

A saturated lime solution will contain 810 ppm Ca and 41 meq/l alkalinity.

But, why go through all this trouble?  Why not just drop a little dry kalkwasser power in your 4 gallon top-off container each time you refill it?  That way you can use a less then saturated solution if needs be.

Maybe I should further explain.  I have a 4 gallon trash can under the display tank (21 gallon ViaAqua) that is the top off reservoir.  It feeds the main tank controlled by a float switch located in the hob sump.  I currently drip kalk wasser via gravity to maintain the ALK and CA.  I want to build a small kalk wasser reactor that will fit inside of the top off reservoir.  The reactor would take input water from the 4 gallon top off reservoir.  The output would then be used for makeup water to the main tank again controlled by a float switch in the sump.

My worry is that the lime slurry in the kalk reactor would vary in ALK levels.  Especially if the kalk reactor stirs up the lime slurry too much.  Thus my original questions:  "In a Kalk Reactor, does the ALK always stay the same?  Is the clear Wasser the same ALK as the lime slurry?  How does one know what to expect the ALK to be on the output of the DYI kalk reactor?"

I hope that this explains my concerns and worries.  Any comments (except "You must be crazy!") or suggestions will be greatly appreciated.

Fred

I want to dose the kalk Wasser directly into my RO/DI reservoir

What does this mean?  Are you metering the kalk into your makeup water or are you metering it into the tank?

Other questions concerning Kalk Wasser and dosing:   In a Kalk Reactor, does the ALK always stay the same?  Is the clear Wasser the same ALK as the lime slurry?  How does one know what to expect the ALK to be on the output of the DYI kalk reactor? 

I want to dose the kalk Wasser directly into my RO/DI reservoir but I do not want to have varying ALK levels as it is metered into the reservoir.  Thanks!

Fred