Ewbie, when you got your Paphs, were they originally potted in charcoal, or bareroot? Maybe you should consider changing the medium into something that can retain more water, or charcoal in finer grade not those big chunks. Dry season is on now in PI and I bet your Paph in large charcoal are going to be very thirsty. You can also try putting a layer of moss on top of the charcoal to help keep moisture, you can always remove it when the wet season arrive.

I particularly like the green moss they commonly use in Philippines. Its unlike the sphagnum moss that absorb and retain water like a sponge. The green moss is springy and dries more quicker than sphagnum. Maybe you should consider using it for your Paph. instead of charcoal.