Fertilizing plants in sphagnum

[bethmarie]

I've been told by a couple of growers to fertilize orchids growing in moss at 1/2 to 1/4 the concentration used for orchids in bark/other mediums because moss retains more fertilizer and it can build up and possibly harm the roots.

I fertilize at 30 ppm Nitrogen at almost every watering. Do I need to lower the concentration even more for my plants in moss? Fertilize less often?