Thank you Ray for your comments. In my case, being new to semi-hydro, I am perhaps unreasonably cautious with respect to moisture, both with my orchids and with my carnivorous plants (which are typically moist-savannah, wetland or bog plants) in order to avoid fungal problems and root rot, and to encourage an extensive root system. I am this way despite the fact that I live in an arid environment with very low humidity (in eastern New Mexico, US).
So far, in my perhaps dozen years with carnivorous plants and orchids, my conservative watering and fertilizing has produced good results and avoided for the most part fungal problems. But then again, I have never done a side-by-side comparison.
I think I'm going to cautiously and watchfully attempt to water and fertilize (weakly) a little more freely with the plants I now have in semi-hydro, and see what happens.
Thanks again for your help and comments, and for being a great resource for semi-hydro with respect to both information and supplies.