I've got an Avast Marine kalk stirrer (on the right) that I will not be using, and would like to pass on to someone who would like it. Seems like a nice way to dose kalk, but I'm doing 2 part and don't plan to go that route. It does work, but the motor is kind of noisy - and I don't see an easy way to change that - thus, free.
I believe it's the K1 model here http://www.avastmarine.com/collections/avast-built/products/kalk-stirrer
I believe it's the K1 model here http://www.avastmarine.com/collections/avast-built/products/kalk-stirrer