Thanks guys!

You know I should have had a talk with Shane Heil before building this... After talking with him last night, I'm thinking a more enclosed (traditional) kalk reactor might be sufficient.  Mine works, but the traditional is a bit easier...

Another nice project!  You have quite the knack for making me feel stupid!

Ok, a couple months ago I found myself not able to keep up with my kalkwasser dosing due to my inconsistent nightly schedule.  And I had a low pH issue.  So I went to work at putting my version of a kalk reactor together so I could automate some of this hassle.

Below is a picture of the container for the kalk.  It contains approximately 5 gallons of dispensable kalkwasser.  The 1/4" tubing and elbow on the left is where the kalk is pulled out from and leads to the dosing pump.  The 1/4" tubing in the center (at the top of the container) is just an emergency overflow so that if my float switches ever stick.  This overflow is plumbed directly into my sink drain.  The whole reactor/pump/control system all sit under my sink with a 1/4" water line fished through the wall over to the sump.  There are two floatswitches that maintain the liquid level between the bottom switch and top switch.  Not pictured is a magnetic stirrer and stir bar to mix up the kalkwasser as the contain fills with water.

Here is a picture showing the "guts" of my dosing pump (back view).  I bought the drive motor from NPS.  It turns at 7.5 rpm.  I also wired in a timing relay ( http://preview.ametek.com/content-manager/files/NCC/Q3FSerie s.pdf) to adjust the flow rate of the pump.  If the motor is on, it's turning at 7.5 rpm, but the timing relay cycles the pump on and off allowing me to adjust the total daily dosing rate.

Below is a picture showing the front of the dosing pump.  I bought the pump head (flexmaster from cole-parmer) off Ebay and I had one of the machinist out here at work mill me a motor to pump coupling to connect the two together.  The pump head came with two different tubing.  I'm using the smaller diameter one.  It pumps 1.7 ml per revolution.  Below the pump head is the controls.  There is a knob (potentiometer) that controls the on/off cycle length and there is a switch to switch between auto (cycles on and off) and on (constantly on).

Below is a picture showing the control relay for this whole set-up.  This is the brains of the system.  The mixer is plugged into the outlet labeled "mix" and the pump is plugged into the outlet labeled "pump".

How it works:  The pump will dose kalkwasser (adjustable by turning knob) until the level in the container drops down to the lower float switch.  Then the pump will stop, a solenoid valve (not shown) adds RO/DI water to the container and the mixer mixes the water/kalk.  When the level reaches the upper float switch, the water solenoid valve closes and the mixer stops mixing.  Ten minutes later the dosing pump starts pumping again.  And the cycle will continue.  I have to manually add a couple scoops of dry kalkwasser every week or so to maintain solution strength.

Why this way?  According to many, the traditional "kalkwasser reactor" suffers from the fact that it's hard to dose a completely saturated solution.  The reactor mixes a few times per day, but there is no guarantee that the water pushed out of the reactor will not be partly (or mostly) the fresh water pushed in.  My idea was to mix up the kalk in batches and use the whole batch up guaranteeing saturated kalk throughout the dosing period.

Modifications to original design:  I found that my magnetic stirrer (also bought off ebay) was not powerful enough to keep mixing when the level got high in my reactor/container.  So I placed a powerhead in the bottom of the container and plugged it into the mix outlet.  This works OK but I'm on the lookout for a small propeller that I can attach to the end of a plastic shaft so I can make a better mixer.

Overall I've been pretty pleased with the results.