Dendrobium speciosum leaves yellowing from tips

[nolaorchid]

Hey guys. I'm rehabbing a gift D. speciosum and in less than two weeks the few remaining leaves have begun to yellow and die. I'm told this problem has been ongoing. The yellowing starts at the tips, then spreads to the whole leaf and they eventually brown and drop.

It was kept pretty dry until I received it, and I have since watered it twice, hoping to plump the pseudobulbs a little. It's being kept in a spot with all-day bright indirect light with a bit of direct sun in the morning. It's been very hot here lately, in the mid 90s F every day/ upper 70s and low 80s at night, but still humid and breezy.

It has one strong new growth, but even the sheathing leaves on that shoot seem to be yellowing. It's not rotting from what I can tell, but I'm defintely being cautious about over-watering. The roots fill the pot pretty well and it seemed perfectly capable of recovering until the yellowing happened.

It's potted in mostly coconut husk and I'm almost wondering if salts are present and building up in the leaves. But I don't want to repot it now with the new growth emerging. The yellowing is progressing pretty fast, so I may just be out of luck.

What do you guys think? Should I repot? Flush the pot with tons of water? Take it inside away from the heat?

Any help is much appreciated!

PS. I'm posting this from my phone, so I'm hoping the pictures turn out ok.