I am going to start a terrarium in a 75 gallon aquarium. I would like to use T5s to light it. it would be about 25 inches from the bottom of the tank when it is completely empty so it would be less then that after the false bottom and substrate in it. is this enough or to much? These are the lights i'm looking into which one would be better.
I think you'd actually have to elevate a 6-bulb fixture higher, unless you're planning on growing really high light plants in there.
I am a discount reseller of Hydrofarm products, and I sell that for $20 less than their suggested retail, but I must tell you that I sell a lot more of the Envirogro fixtures than the designer ones, but if the decorative upgrade is important, go for it.
The 75 is 48 inches long. Do you think I would be better off buying the 4 bulb fixture? How high would I have to raise the 6 bulb fixture to grow medium light orchids?
I really have no first-hand experience with them. T5HO lamps are pretty bright, though. I had three 2', 24W lamps about 20" above the medium in a terrarium, and fried a few low-light plants.