I would like to convert 3 aquariums to terrariums. They are 10,20 and 30 gal.
Can the new T5 grow lights, 2'long do the job or is it too much light if it sits atop the terrarium? I like the idea of a little less heat in the terrarium. I plan to grow mini and micro mini orchids in them. Don't know yet what tolerances they have.
I think that T5s will be a good solution here- perhaps in the 30G you might want to use two of them staggered so that light makes it to the ends (though honestly I do kind of like the spotlight effect with the centre illuminated more than the sides). They do run relatively cool, as well.
The 10G might be a bit of a problem because it's not quite 2 feet long, but if you don't mind a bit of overhang you'll be alright.
I started with a large aquarium then decided to have a custom tank made. The t5s are fine as long as you use a fan to blow away the heat before it gets into the tank. I describe all this in my article at: Setting up A Custom Orchid Tank - Orchid Board