There is no guarantee that a clown will take to an anemone. Especially if the clowns were tank raised.
You can use your regular water testing kits to check your tap water. But even that won't give you the whole story. You can also take your water to most LFS
's for a more thorough testing. But honestly it for want to get into more delicate animals for your system, a RO
purifier would be highly recommended.