dd writes:
over the surface of the medium usually will suffice.....calcium
deficiency is sometimes ovelooked because it has been called sunburn
or it is confused with the damage caused by excessive use of dry
fertilizer. An overfertilized cattleya will first have blackening of
the younger foliage (not just the new leaf, as in calium deficiency)
and possibly some of the odlder leaves as well. In severe cases, root
injury and the death of the plant may ensue.

Ok, no, there is no calcium in my fertilizer. So this will likely also
be affecting my vandas, then?

Thanks for the tip. I'll see what I can do tonight.

Geir