as long as your topoff doesn't go crazy, it should be fine. depending what type of ATO you have, it should just pump in small amounts of kalk at a time.
i'm using an old rodi housing. I changed the plumbing so the line that goes to the bottom of the housing is the 'in' there's about 1/2 cup of mrs wages in there. as the water gets pumped in it stirs up the kalk, and pushes solution out the top.
