Confused about using Kalk Reactor

[speedingredline]

So I have a Barr Aquatic Kalk Reactor. Didn't come with any directions, and can't get an answer from them. How much kalk do I put in this thing? I have it attached to my RO/DI reservoir, it is gravity fed from the reservior then drips into my sump. Do I just dump a bunch of kalk in and forget about it? How can I calculate the amount add if the reactor is constantly filled from reservoir.

Thanks