Okay sorry to pull this thread back up! :) So I'm just curious - how is it that the MH drops from 12,500fc at the bulb to 850fc at 1 ft away, whereas the T5s only drop from 2900fc to 1500fc at 1ft away? Is it a result of the MH being a point source versus the T5s where the length of the tube emitting light 'adds' to itself?

The reason I ask is that I'm setting up 2 encosures - one that's relatively taller which I hope to use the MH bulbs I have (and that oclearis totally helped me out on), and one that's shallower which I hope to get the T5s Ross recommended.

I'm realizing now that I'm doing more indepth research what a huge bag of worms this entire lighting thing is, and all the controversy there is surrounding this topic. Being poor that I am, I don't have the luxury to try different things so I want to be sure.

I was reading on another forum that for price purposes, people even go with T8 lights and overdrive them...besides the fact that wiring stuff scares me, I'm not really too keen on this since I feel like the lumens/watt go down, despite the fact that you're getting brighter light.

Well, the T-5 do have a more even output of light for low height shelves. I believe they should scientifically drop off at the same rate, but since the fluorescent tubes are over a much wider area, it's easier to get close to the maximum possible drop off. Where as with Metal halides only at the very center will you get that max.

T-5 are a high output T-8 basically. By default the T-5 ARE a high output. Where as the default T-8 is a normal output. That's where the greatest increase in lighting comes from. Not that T-5s aren't a decent increase in efficiency, but the nature of the game is lopsided in their favor.

If you're on a budget, you can pick up a 4-8 tube T-8 setup for under 50$ at any home depot/lowes, and will be sufficient for phals/paphs etc... anyways. If you really want to kick the light up a notch, T-5s are the way to go, but just because it's a newer technology doesn't mean it makes all the past obsolete.

I agree with the above. There are lots of Orchidboard members successfully growing and blooming various orchids under t8 setups.

Makes sense -thanks oclearis!

I found good T5 bulbs being sold at a reasonable price at a local hydro shop, so I think I'm going to go with the new-wave fixture you recommended, Ross. It fits the size of my tank better than anything else.