Two shelves are now loaded with orchids as you can see from one of my images. Roughly 40 plants are there in total.
The second image is of an inexpensive light meter I found on the Internet recently for $18.50! It came today so I was checking the levels of footcandles under the T-5 tubes.
Center of fixture, 4" below tubes, 6,000 foot candles!
End of fixture, 4" below tubes, 2,700 footcandles. Same area, 6" below tubes, 2,200 foot candles.
Center of fixture, 6" below tubes about 3,500 foot candles.
As an example a standard Cattleya requires approximately 30,000 foot candles of light per day in order to flower properly. In my set up, center of fixture, that plant would need to have the lights on for about five hours. 30,000/6,000ft. Candles= 5 hours. So if there were Cattleyas under the lights they would do best under the center of the tubes.
If I take the same plant but put it at the end of the tubes, 30,000/2,700= 10 hours. That plant would need ten hours with the lights on to flower at the end of the fixture.