Do I need more light?

[MermaidNat]

Hi everyone, I'm a long-time aquarium and tropical vivarium enthusiast itching to get into orchids. Last weekend I came home from the local botanical garden's spring sale with 10 low- and medium-light orchids priced at $5 each, so I guess you could say I dove in at the deep end. A few are in bloom, all are showing new growth, and I am planning to convert to s/h eventually.

I moved all of the pots into a 36x18x24 inch ExoTerra outfitted with two full-spectrum LED fixtures designed for freshwater planted aquarium use. My main reasons for enclosing them is that my household humidity is too low (~30%) and my windows receive very little light, so I'll most certainly need to supplement them.

Lux readings in the terrarium appear to be too low for the requirements I read in the literature. At the very top of the tank, I get 15,000 lux, then about 10,000 lux at mid-level. I can easily create tiers with eggcrate to bring plants closer to the lights if needed; however, I'm thinking maybe I'd do better with buying an additional light. Does anyone have any suggestions?

Here's what I have in the enclosure:
- Odontocidium Wildcat #13
- Oncidium tsiku marguerite #1
- Oncidium Hula Halau "Volcano Queen"
- Dendrobium (unknown noble species)
- Dendrobium chocolate chip
- Dendrobium fuchs blue twist x compactum
- Potanthus triple love NN
- Brassidium Nittany Gold "Dr. John"
- Sarcochilus Snow White Grumpy x Snow White
- Miltassia Charles M. Fitch "Izumi"
- Paphiopedilum makuli-curtisii maudiae x maudiae "Napa Valley"

I should have started out more gradually, but I couldn't resist the prices at the sale. Once I get enough posts, I'll add some pictures.

Edit: I just did some browsing through the forum and think I may be ok with my current lighting setup. I saw in another thread that artificial lights can be roughly 50% of the output mentioned in orchid care charts, as those charts are recommending peak/noon levels. If I'm correct in my calculations, my low-light (10-16K lux) and medium-light (17-30K lux) are getting enough light in the terrarium with the 10-15K lux output, depending on the levels.