Jackie I was just looking at your thread again and wishing I had some answers. I know this has to be killing you.
I went to one of my Chid books for reference. The only photos resembling your leaves had damage due to temperature extremes. We had a chilly winter but you mentioned the condition happened recently so I think we can rule the temperature thing out.
Remember when Central Florida had a week of consistent evening/middle of the night rainfall a few weeks ago? All that moisture might have set the stage for a viral or bacterial infection. My sheltered plants growing in sphag mixes stayed moist that week despite me not watering them. Does your chid hotel permit rainfall to reach your plants?
If you don't see bugs then we've ruled that out too.
Is it possible that you have a build-up of fertilizer salts in the lava rock?
I'm sorry I don't have a definite answer, but I would suspect your problem is related to that week of steady rainfall. I'm not familiar on how to treat viruses and/or bacterial infections. You've probably already done a Physan treatment but we both know it's not a cure all. If the plants were mine I'd give them a Physan and systemic treatment, remove them from excessive humidity, and ocassionally mist their roots. Then I would gradually introduce a little superthrive and fish emulsion fertilizer. This will probably be a slow recovery and at best it's likely you'll loose your leaves. If your patient and nurturing you might get some basal keikis in a few weeks...or not. I'm going with my gut instincts here. Wishing you the best of luck.