If I am not mistaken the longest 96 watt they make is 36". A lot of fixtures that are for 48" tanks use a 21" bulb so that they dont have to stagger them. However dropping down to that size also drops the watts down to 65 I think. On the other hand if you want lights that would go the entire distance of the tank without staggering them or running two side by side a company called Current came out with a new PC
a while back that is, have to refer to my referance, 44/1/4" long that pumps out 130watts. This fixture by Current is called the extreme orbit uses 4 of those bulbs at 130watts each with moonlights and is somewhere in the $550 range. That retro is looking a lot better in my own opinion. Another option is using using standard flourescent tubes, either HO
but I dont know what type of ballast you got and it sounds like it is prebuilt for PC
I'm just south of Casa Grande in the dustbowl of Az called Az City. LOL
Hey sorry I totally spaced there for a second and overlooked the previous owner had them on a 36" tank. Everything I have said up to this point will still work however you will probably need to get a new reflector. The one your getting is only 36" and will not fucus all the light completely into your tank. Here is a link for a brand new reflector that is 48" long to fit your canapy just right. And as an added bonus the company that sells this can also rivet the bulb holders into it so all you have to do is screw the reflector to the canapy and put the bulbs into the pre-installed bulb holders. Then just hook up your wireing and secure it so that no wires are drooping turn it on and you should be good to go.