Opinions needed from all you hardcore Coral growers

[howdy20012002]

So I am in the process of a setting up several tanks for growing corals out and fragging and just wanted to get some input
should I set up a separate quarantine system for the corals?
or will having separate tanks but connected by a common sump be sufficient to keep any problems or diseases from spreading?
are diseases mostly contact to contact or are they water borne that would just go thru the overflow into the other tanks.
so what would you do?
the big thing is I don't want to have to buy yet another large skimmer.....and another sump.
thanks in advance for your input
Neal