[flyingSquirrel]

Others with more experience could confirm or deny some of the more unsure points here:
Raising the lights will result in light fall off. If you have plants at the lower portions of the tank you should consider that.
Cooling a light fixture with fans is recommended in some cases. I would mount one fAn at the end of the fixture blowing in,and one on other side blowing out that will get some real exchange going. There's a good video by user: james67 on these forums with excellent instructions. On laymans fan assemblies. It helped me. If you also do fans inside the tank there are plenty of other drawbacks. Search around a bit on the forums for fans air circulation etc. btw for a tank you size you'd need larger fans. The 2 40mm just won't cut it
amazon.com has lots of supplies

 

[flyingSquirrel]

funny, i remember james67 showing 40mm fans in that video....
it depends on the fan your using. the 40mms i use push 24cfm at max power. 2 of those might be overkill for a 55. and now delta has come out with a new line (louder and unavailable yet) which push 27cfm out of a 40mm (18K rpm!)
james

Ah yes, sorry. I didn't know what I was saying...Note to self: don't take a sleeping pill and then try to give advice on a forum. Apologies to everybody here for that slip up

And btw, wow, those are some crazy 40mm fans! Damn, I can't believe the cfms on those tiny fans. Apparently I made a mistake when I bought 2x 40mm that are only 5cfms..