Vanda leaves purpling.. ok or not?

[orchidjunky]

Hi all, I received a Vanda from a friend that is in vase culture. I am not sure what the light was like at her house but I think she had it in a window indoors. I grow my orchids under a grow light and I noticed that this vanda is getting reddish/purple tones on the upper leaves. I've read mixed opinions about it. Some people say that it's a sign the orchid is doing well light wise. While others say it's a sign that there's too much light? It currently gets 3 hours of east facing sunlight and then 6-7 hours under a grow light with about 12 inches of distance from the top leaf to the light. Should I move it or just leave it?