Dracula leaves yellowing from the top down - sunburn?

[Zyzzyzus]

Hello,

I have three clumps of Dracula lotax in a terrarium. It seems like the leaves are slowly turning yellow from the top down, and then dropping. I know Dracula's are finicky, but this one is supposed to be easier. All three clumps are pouching out a lot of new growth, too. I've tried searching to see what yellow leaves can mean and haven't found anything conclusive. Is the leaf yellowing a sign that they're getting too much light? Or too much water? Or...

Thanks!

[King_of_orchid_growing:)]

It's best to post a pic. I can't tell from your description. Not enough info.

Temp?

Light?

Humidty?

How're the roots?

What does the potting media look like?

How are you growing it, mounted or potted?

What kind of water are you using?

How often are you watering?

What's your fertilizer regimen like?

You get my point…

I also posted a general guide on how to grow Draculas in the Pleurothallid Alliance Forum.

http://www.orchidboard.com/community...acula-spp.html

[Zyzzyzus]

Oops sorry, here are some answers.

Temp: daytime 66-70 Nighttime:60ish.
Light: it's about 10" from a 9 watt Jungle Dawn LED
Humidity: Not sure but based on my other terrarium probably 75-90%
Roots: a couple that were above the surface are dried out like pale beige hollow tubes. some roots are green and some are sort of brown/slimy.
Potting media: is ABG mix (charcoal, tree fern fiber, sphagnum moss, bark chips and I forget what else)
Two clumps were potted directly in the ABG and one clump is mounted on some cork with some sphagnum moss around the roots.
I mist every couple of days. They stay moist but aren't soaking. Occasionally they might even become dry.
I haven't been fertilizing at all
I water using either distilled water or tap water that has set out for a few nights or bottled spring water. Mostly it has been bottled spring water.

I've taken the two clumps out of the potting mix and now they're just sort of lying in there. Unfortunately/fortunately all the leaves left on the plants are fully green.

[King_of_orchid_growing:)]

Might just be an old leaf.

Plants looks fine.