Hey Chad,
You definitely do not want to have a calcium hydroxide in solution and moved around by a recirculation pump in the RO/DI.
I'm not the most experienced in the hobby, and will let those with much more knowledge than me give their advice and recommendations, but you definitely want the powder to settle and not float around.
I have my auto top off running to a fluidized reactor (its a freshwater aquarium sand filter) which feeds the tank RO/DI water which flows through the reactor, resulting in kalkwasser which then goes into the sump and into the system.
The whitish paste you would have if you stir is not something you want in your system. Every time I fill up the fluidized reactor I wait a few hours until the cloudiness in it decreases and finally the water at the top is completely clear.
My understanding is that RO/DI water is so pure and so clean that it soaks up all the calcium when if flows through the chamber of the reactor.
Here's what mine looks like - you can see that there's a float switch, in the sump, and a line coming in from my reservoir. The water goes through the reactor and becomes kalkwasser which goes into my system.
I hope this is helpful, and those who know more should give you more info
