What Alex said is some very good advice. I've been retrofitting my aqualight with new fans and found similarly that having some blow in, some blow out gives best results. Probably a bigger factor is the airflow due to openings as mentioned. This is why I'm adding a clear cover to the bottom of my DIY AHSupply enclousure so the only place for air to enter and exit is through the fans. All air will pass over the bulbs and bypass is eliminated.
Alex, what's the make/model of the current fans you have now?
Alex, what's the make/model of the current fans you have now?
