Sunslight, "Checking the actual, inside, dimensions of the shelves, I came up with approximately 46x16." Actually, I have one of those shelves right here beside my computer, in use to hold my computer, scanner, video camera, CD drawers, and a bunch of books. I bought three of those shelf units, and I have one of them in use as a fluorescent plant stand right now. The distance between the posts is actually a bit less than 16 inches. I measure about 15¾" between the chrome posts. The distance between the heavy wire structure at the bottom ends of the shelves is about 46¾ inches, maybe a hair more. However, that should be not problem, because you hang the fixtures from the wire shelf above the shelf, and the fixtures can extend well beyond the end of the shelf, if need be. I use 1" S-hooks to hook over the wires of the overhead shelves, and the lightweight chains that came with my Home Depot shoplights. The chains let you adjust the height of the lights to keep them reasonably close to your plants for the best results. That leaves the problem of how you fit three fixtures in the relatively narrow space of 15¾ inches. There are several possible solutions. For your 50" x 6" fixtures, you hang them in a "staggered" configuration. Hang two of your fixtures snug against the poles, down a few inches lower than the minimum hanging distance, and hang the third fixture higher up and centered so that its light can come down between the other two fixtures. A variation on that would be to hand the outside fixtures at enough of an angle to allow the third fixture to fit between them. That would put your three fixtures in sort of a "hip roof" configuration, fitting between the poles and protruding a bit beyond the end of the shelves. A third possibility would be to hang all three of your fixtures at an angle, in a sort of "venetian blind" configuration. A fourth possibility is to buy some narrower fluorescent shoplights. Home Depot has $8 48-inch T8/T12 shoplights that are only 5 inches wide, and three of them fit neatly between the chrome wire posts. Since Home Depot sells a box of 10 Philips Cool White T8 bulbs for $19.95, they cost only $2 each. They draw only 32 watts each, contain less mercury, and are more efficient than T12 bulbs, so they put out as much or more light. And their lifetime is rated for 20,000 hours, which is a long time. Another advantage of the Home Depot Commercial Electric shoplights is that they can be converted to "overdrive" your tubes for at least 50% more light output per tube. That would give you the light equivalent of 9 tubes per shelf. MM

brickeyee, I say the rust will reappear because oxygen and moisture (that's what you meant to type, not "mosite"?) are always present. We live in WNY, and the humidity is high in the summer. I'm afraid that leaving those cast iron parts nice and clean will mean rust sooner or later; iron doesn't have to be wet to rust, it just needs moisture in the air. So, as you say, one or the other has to be restricted, and that is the problem, I guess. There is a very little bit of the original finish on these parts, just a little, but it looks as though they were either painted gold or perhaps bronzed. (Although I have to ask what happened to the bronze if that is the case. The finish is left on some of the high-relief areas, not in the crevices, and you'd think it would wear off of the high points first.) Argh. My husband just wants to hang it as is, but once it's up, it's up. And I don't like the rust.

Is it really necessary to have separate switching of the two lamps in the cases? If not, then you can just use an ordinary small can type 2-lamp electronic ballast and fit new T8 lamps. That's the easiest answer. If you do need separate switching then you'll just have to find room for two ballasts. Usually if one will fit, two will, if placed end to end. You will probably have to drill and tap new holes for the second ballast. If room is extremely tight in the fixtures, maybe you could remote the ballasts. Another possibility would be to use 3 or 4 PL type CF lamps. The mag ballasts for them are usually very small, about the size of a voice coil transformer from an AC-DC table radio (if you're old enough to remember those). You'd have to change out the lampholders too, of course. I see many hours of labor in your future. ;-) Maybe new T-4 or T-5 undercounter fixtures would fit in the cases.

I also use 2 per shelf. One recommendation I would suggest is to make the frame slightly longer than 48" so that shop lights aren't pinched. I drape 2 small chains over each end and have each shop light chained to a dowel rod with finishing nails in each end. Then the lights can be easily raised or lowered by positioning the nail end into a different chain link.