[Oscarman]

My thoughts are 2 tubes T5 for a 16" wide shelf.

I have some mini Catts under 2 T12's and added 1 T5. The plants are about 3" away from the bulbs and they started to display some reddish/purple color change in the leaf margins indicating the lights getting a bit too bright.

Right now I have a 3' x 2' wide with 2 T5's that I am going to use for paphs and phals. The plants will be 4-6" away from the bulbs. A friend grows his Paphs and mini Catts 6-8" away from 3 T5's and has not trouble blooming either. His grow space is 24" wide.

I don't think the wattage of the T5's from Home Depot are as high as the ones from the hydroponics stores.