the box is a 10"x10" i added a 4" high velocity fan $5 from walmart and a timer from home depot that i mounted on the top.
this shows how i added mesh inserts for air circulation since i have a 400w ballast in there.
prior to wire tying everything tight
on the left i have a 10' power cord and a 1' timed out for fan or multi ballast control from this timer. it is not connected to the ballast only to the timer. on the top right side i have a long and short set, those are the night/day from relay. the bottom right is a timer/relay bypass plug that connects directly to the ballast so if either t/r should go out i could still use the ballast easily. i left the switch for mh conversion inside on the ballast mount, i cant fit mh in my cool tubes atm so no use yet.
this setup works with my ballast and in my situation. your situation may be different. wiring this is definitely not for everyone but if you are comfortable changing a ceiling fan, it should be no problem. i never imagined the possibilities untill this thing started flippin over my plants like the sun over a horizon
*edited to add this wire diagram...