Will my tank overheat?

My new tank is a 68g. 36x18x24. I'm running 2 175w halides and 2 t5 actinics. Halides are about a foot from the water. Lighting is in a canopy. The back of the canopy is open. I'm also running a mag 9.5 for return pump and another mag 9.5 for the skimmer. I'm worried that the heat from the lights and pumps may cause the water to heat up.
Will a fan blowing from the back of the canopy in help out at all? Should I have the fan sucking the air out of the canopy?
Tank is not running yet but I would like to see some input on my options right now.

Fyi my house temp is usually kept at 68 all year round.

 

The MH will definitely raise your temp above your house ambient temp. My question to you is do you have atemp monitor for your tank and if so what is the water temp now?
Yes a fan will help reduce heat but usually contributes to evaporation. The fan should be set up to blow across the water. What I did was drilled holes 4 x 1" at one end of the canopy for the fan to suck air in and 4 x 1" holes drilled at the other end for hot air to exhaust. Since your canopy is not fully enclosed just get a small clamp on fan and place on one corner aimed diagnally across the length of your tank towards the back to exhaust the heat. Hope this helps.

 

Tank is not running yet. Hope to fill it next weekend.
So 2 fans would be my bestbet? One pulling in air and one sucking the air out?
Hopefully that might help if I have a issue. Thanks

 

One will work if it is fairly strong, if it is weak then two.