Argh! I wrote out an entire thing and it dissapeared
Oh well here we go again.. the answer to your question is YES! Most definately. I had to build one when I started a Reef tank, but realized the yellowness was perfect for plants only.. and not corals :P - OKay I am going to assume you know what a ballast and all is.. if you don't, just ask. At Lowes or Home Depot you can buy a ballast by Sylvania that powers two Power Compact 65 watt 6500K bulbs for about 24 bucks. If you want one that powers one of those bulbs, they are about 13 bucks. As for bulbs I used the Lights of America spare bulbs that they sell. The issue with these bulbs though is that instead of being flat, they are circular.. but I am almost dead sure they sell flat bulbs, and I'll look for some tonight or tomorrow for you. The bulbs I got were 12 bucks each. After you get the ballast and bulb, you need (depending on the bulb) a base to plug the bulb into.. which can either be a mogul base (like the Lights of America were), or a pin kind, or even a regular screw in base kind. Oh yeah you also need a plug that will need to be sodered to the ballast, so you can actually power the ballast! After you soder the plug to the ballast, you will then need to soder the base (the thing that the bulb screws into) to the ballast. Now depending on the bulb.. you may need to soder the innerds of it. The Lights of America bulbs I had to soder the innerds. The reason being was that inside the base of the bulb was a capacitor that needed to be cut out and then the wires re sodered. The reason for this was that the bulbs were made to take direct current, so the capacitor was placed inside the bulb. The problem is that the ballast you will get from home depot or lowes already does this job, so double limiting the power going to the bulb will produce a very very dimmed light. Well after you get everything sodered you just need to attach the set up into the hood, and screw in the lights.. and voila a great freshwater plant lighting system. But again this depends on the canopy and tank size.. If you want I can post pics of my project and show you more or less what I did during the construction of this.