Paph Leaf Problem
 

Can anyone take a guess at what this leaf problem is? I have numerous Paphs
of several kinds (species, primaries, and novelties), and they all seem to
get this type of spot on various leaves on a regular basis. When I cut off
the end of the leaf, the problem seems to stop spreading for a couple of
months, and then the leaf starts to die (becomes dark brown) again (starting
at the end of the leaf). Is this just natural?

http://216.160.131.65/LeafSpot1.jpg
http://216.160.131.65/LeafSpot2.jpg

Environmental Details:
Grown In: Medium Sized Coconut Husk
Plant Food: "Grow More" Urea Free 20-10-20
Watering Schedule: Every 4-5 days
Temperatu ~75 degrees F.
Lights: Natural and 4 Foot Cool-Warm Bulb (Mixed)

Please let me know if I can supply any more details or additional photos...



Thanks for any information or opinions!!!!
Frank