I think it is great!! I have been dosing kalkwasser to help keep my calcium up for a few months now, its taken me a little while to get my dosing schedule worked out to keep my PH from spiking too high while still maintaining my calcium levels.
PS
I have been using Mrs Wag es Pickling lime to mix my kackwasser, its about $2.75 for a pound instead of $12 a pound for something labeled for aquarium use.