Need help-tank is leaking...please

hi i have 55gallon reef tank-about 4-5 months old...
3 fishes and 4 frags corals...
just did water change 13gallon and my bulkhead is leaking-return to sump bulkhead 3/4".
actually two is leaking one more then other...
they are glue in to acrylic tank.
how i can fix them??? silicon on outside ore what?
what i do with fish and coral. i don`t have other tank... how long they are good without sump-protein skimmer...
i just move heater ti Dtank and drain water below bulkheads...
anybody???
please...