I'm always trying to grow different orchids so, again, I got come Corybas bulbs, plus some Orchis, Nervilia, and Anacampis bulbs. Since we are serial over-waterers we used different medias. The Corybas went into a mix of sphagnum and perlite which we tried not to water (too much) - failed. The Orchis bulbs in a mix of Bonsai type small stones and a little bark did 50:50. The Nervilia in organic mix is OK. And the Orchis and Anacampis in the sandy (VERY DRY) mix is 100% survival. My question is, since the plants in the sand mix survived the hibernation phase, should I change the media, now that they are coming up?