NO T5's run cooler than PC
's get HOT!
T5's are slightly more efficient at producing lumens or light per watt.
T5's penetrate deeper into the water
's are basically T5 tubes but they are bent around into a "U" shape, since they are 2 bulbs very close together, they get hotter. Also since they are closer together, the reflector cannot be as good/efficient.
Individual reflectors and T5's is hands down better than PC
Please search around on many forums for Odyssea
, as you will find some good and many bad things about them. They are cheaply made, and that listing says T6 bulbs, which are hard to find and I dont think you can get quality bulbs for it.
Also, for a 4' tank, you can find better deals on T5's then any other tank size. That catalina fixture is the best bang for the buck period, its a great fixture!
And no I dont have one, I'm using a T8 shoplight ODNO at this point, b/c that fixture would be too much for my 55G(for me)