So I did the DIY thing and made one of these out of a house water filter and turned it into a Kalk stirrer (this is in the archives if anyone is interested). It is connected to my osmolator for top off purposes. The unit just flows waater down a small tube and slowly mixes the powder, but is not on a timer like some of the commercial units. But the million dollar question is how much KALK powder to put in at a time. In reviewing some of the threads on the net they reccomend filling the container a third of the way up and that would end up being roughly a months supply, but I have noticed my Ph which has been habitually low (8.1) creep up to around 8.3 (which is good) in the last two weeks. Problem is I do not want it to overshoot and am a little baffled on how to control it. Suggestions welcome