Had to hook up a 6in fan to keep the tank temp down(35.4' C

)
The back of the canopy is open so I secured it to the back,blowing air towards the front.Should I put in on one of the ends of the canopy for best results?The temp has dropped to 28C in a couple of hours.
I'm running a 250w 10k mh and a normal actinic bulb over my 54gal.