28 gallon HQI JBJ nano
 

Hey! Hopefully someone has an answer for me. I bought a used setup and when cleaning the fans and replacing bulbs before use, I noticed the fans all force air to the inside of the reflector. Is this correct? Wouldn't it be more efficient to run 2 in on one side and 2 out on the other to get cross flow across the bulb?

Any advice would be great here. I'm about to screw it all together and don't want to take it apart a day later if my concerns are correct.

Thanks in advance

Ideal setup for four fans is to have two blow in and two blow out. You are correct in your concern that the fans were NOT set up properly when you bought the used system. As you already suspected, all four blowing in will result in trapping much of the heat inside your canopy/lighting system, whereas having 2 blowing out the heated air will dissipate that heat into the room, thus cooling the tank (important in the summer time).

Basically a 'push and pull' setup with the fans.