I dose kalk regularly as top off. I let it sit for a day so that I can add only the clear water. After the clear water is gone I then refill my container with more RO water (no additional kalk) and let it st and use this to top off. I do this a couple of times and then dump the dregs. Is there any harm or benifit in doing this? I figured I could benifit from re-using some of the kalk the sits at the bottom of the original mixture.