Intentionally introducing sundial snails

[nlreefguy]

So I spotted some sundial snails on a colony of zoos at my LFS and I picked them up, hopefully to take care of a little problem I have. There is a spreading colony of the plainest looking zoos of all time taking over my best acros, creeping ever so slowly up the bases of the corals. I am hoping to get rid of them with these sundial snails. I picked up three of them and I am wondering how many I should put in - just one or all of them? Any opinions?