[Correction to my original post: water/fertilizer solution of 1/3rd
strenght s/b 1/6th strength.]

Thanks Aaron, Danny and Pat. Your feed-back has help put some things
into perspective.

I began using this fertilizer concoction early in 2000 after reading
an article about windowsill growing in the Dec 1999 'Orchids'. The
recommendation was to use a bloom booster year around. It has worked
well for me with no apparent problems until this season.

I began to suspect deficiencies or toxicity when the only info I could
find for yellowing of middle to older leaves seemed to shotgun trace
mineral shortages. Although, some potential excesses were listed.

The reasons I began using this concoction we

1. To use a bloom booster formulation year-round to help simplify my
in-home growing of cool-dry-rest Den.'s that require a variety of
tweaked conditions to make them all happy enough to bloom.
2. The crystalline fertilizer was chosen because of it's 100% useable
Nitrogen content. Plus, some micro-nutrients were available from it.
3. Because I am always suspicious of manufactured chemicals which I
assumed the crystalline fertilized was, I added the fish fertilizer to
try to cover making other micro-nutrients available for just-in-case.
I assumed the high Phosphorous would not be a problem. All I was
trying to do was elevate the P-K above the N and make trace minerals
available.

This has worked well for me since early 2000. It has been only this
growing season that the problem has begun to show severely on several
plants. What I am now considering to be the indicator for this is a
plant I purchased in 2000, a D. falconeri.
The vendor didn't want to sell it to me at that time because he had
had a "bad water" problem with them and they were still recovering
from it. I brow-beat him into selling me one anyway. It has grown well
for me until this season. It is now one of those plagued with
yellowing and die-back from the tips of the older leaves.

I am going to reassess my fertilizer regimen, lower the phosphoric
acid content and not worry about micro-nutrients. In the meantime I'll
do a thorough leaching of the pots and mounts to clear them out, then
take another run at it.

Thx for your input.
S V