depends a lot on your res I'd say. some details may help. I hooked my chiller up to a 55 gallon res and recirculate there, but I was running a rdwc/ebb and flow kinda hybrid deal. I used flood table bulkheads and 3/4 inch pipe to 3/4 inch barbed fittings.I know you can't see any details there but one of the bulkheads has a piece of 3/4 inch tubing running to a pump at the bottom of the res, it just recirculates thru the chiller and back to the res. when I was running this system as hybrid rdwc/ebb and flow ( dunno wtf to call it actually) this worked well for me.
you gotta get water too and from somehow, if you gotta punch a hole you gotta punch a hole, you won't find a drillbit large enough for a bulkhead to fit so I suggest a unibit, the hole is like one and one eighth inches I believe. you can get a unibit that goes that large at home depot but it will cost you 55 bux, if you have a harbor freight they sell a two bit set one small and one large for 20 bux.Thanks dbkick I can see that you created holes in your res to fit your chiller , I think I may have to do this , but I was trying to avoid this as I have a store brought system.