[Delphinus]

Have you thought about using a float valve for topoff? If so you can just make your topoff water kalk. That's what I'm doing, I'm sure it's way less effective than a kalk stirrer but I believe it has some effect still. I wasn't happy with dripping kalk separately, it was more hassle than just making all the topoff kalk. It's hard to make tangible the effects of both kalk and a Ca reactor but I beleive I'm better off for it. I use a Kent float valve on my 75, it has clogged once in a year. On my 72g I use a humidifer float valve, much cheaper than a Kent valve (1/3 the price) but the orifice is far too small and with kalk it does clog about once per month. I clear the clog by taking a syringe and shooting water in the line, and then it starts the flow again. I never had clog issue with the humidifier valve before I was pushing kalk through them so I know it's the kalk. I was thinking of following Tangoman's suggestion and drilling the orifice out a little larger. The hole is very small (after all it's indended for household supply pressure). Anyways some food for thought: a float valve, either the $30 Kent valve, or the $10 humidifier float valve but with extra maintenance or a wee modification. HTH