There are plants of Paph. Sandcanh (canhii X sanderianum) out there and the pic I saw was pretty cool: 8" blooming plants in 4"-5" pots with 2-3 flowers on a single spike
When I water, I use only water. I foliar feed 2-3 times a month in summer, and I use a tiny bit of slow release fertilizer in the pots.
Regarding cnycharles comment above, I grow Mexipediums hot, humid, and bright!
I grow them in a bark/peat mix, in 3" pots, and water every 5-7 days.
The big plant is in an 8" bulb pan with peat/gray rock mix and gets watered the same.