[Sk8r]

I put in half a pound of kalk once a month. I use a Hanna stirrer, and have recalled something I knew when I worked in a lab: you might as well have the 'hood' liftable [screws taped to the cord, for safe storage] because as the stuff changes viscosity due to depletion, the stirrer-magnet can get cranky or even stall and bog the stirrer rod down in kalk sludge, so it is rather like glue and not being stirred as it ought. This is the stirrer's fault. If this happens to a Hanna, do not hesitate a heartbeat about taking the hood off and letting it run on your kitchen table until it has gotten its speed back up. Then you can usually put the hood back on, install it, and get it going again quite nicely. They're great stirrers and practically indestructible, but they do have that quirk.

For anybody keeping sps in a 54, I heartily recommend a kalk reactor: from daily fussing and rise and fall of alk/cal, I've gone to once to twice a month fussing. Life is good.