How and how long do you quarantine corals and other inverts?

[Coral Hoarder]

i dont iether i buy corals weekly so qt would be usless they get diped then put in the tank i do have two tanks and say i get a new yuma (yumas can get bacteryal infections ) i would put it in the tank with out yumas tank A and when im sure its clean it can more on to join its buddies in the other tank tank B
same thing with zoas its just incase i miss something during dip