I just bought the light fixture for our 90g, its the 36" Current Nova Extreme Pro, 6x39w. I really lke this fixture. We had it before on our 46g, and sold it when we took down that tank. Stupid move, but oh well.
With the NEP fixture, it has mounting legs,or there is a mounting kit the I thinkyou can attach to the hood. On our 46g before, my husband installed some 1"x2"s in the hood to hold the fixture in place.I think he plans something similair for this tank. Right now I have it on the mounting legs over the biocube, Cuz the light is soo awesome!
We plan to replace the bulbs soon with Geieseman, ATI's and such for better PAR output, because the Current bulbs suck.
I researched all the 36" light fixtures for about 3 weeks, then decided this is the best, then shopped all the websites to find best price. Ended up being Drs Foster and Smith for $311 with $9 shipping.
I also priced out doing a retro kit. For $430, you can make a 4x39w fixture with an icecap ballast.