Yeah...I'm with Diane. pH is a hydrangea thing.

While temp and sunlight can effect some orchid flowers' color to a degree, genetics have a much bigger impact. These blue violaceas are a rare recessive trait that's been line bred into the Ooi and Krull type grexes. Even from a Krull selfling cross, so many of the offspring will be violet, and only a few blue and the other odd-balls, such as white.

If you buy seedlings, compots or flasks, you're playing a percentage game. A few might be blue, but many won't. It doesn't mean they aren't lovely. You just have to manage expectations.