Thanks for the advice, bil and camille! I definitely want to build a rain catchment system, but it's having to wait in line behind some more urgent house maintenance. I'll try distilled with some fertilizer in the meantime.
The small fry in front of the Phal are a Vanda Pachara Delight and a teeny Ren. Kalsom. (If I buy small orchids, they don't count towards having "too many" plants, right?
)
I just potted up my box of baby Den. samarai in little baskets with some moss around the roots and bark in the bottom; I hope some of them make it through. ^^;