Thanks Bev, and tarev, Yes they do prefer rain over all else, and that can be a problem for us occasionally. When we have a lack of rain, I do water with distilled. I have on occasion watered with tap that has set for at least 24 hours, and I've not seen any huge 'dislike', but I try to play it safe, and keep distilled on hand.
What have you found with the Pings? Are they at all picky?