Thanks for the answers...I have a few more questions.
Steven, what sort of pump are you using with the float switch? Dosing pump or a regular powerhead?
Also, wouldnt the mixing vessel need to be airtight to maintain the kalk's potency?
I'm using a MJ900 which is well within the amperage rating for the float switch.
Regarding keeping the vessel airtight, I still have some research to do... currently I plan to put a semi-airtight cover on the 5.5g, so not much 'new' air would be introduced.
Steve