^+1 ~ I second Nat's post...
And as long as the yellowing leaves are the bottom leaves, and they don't have any squishy brown/black/or clear-ish squishy, &/or water-y spots on them, leave them be as well (any combination of those are bad). These leaves will also provide some nutrients to the plant as they die back, just like the spikes do.
Just keep the Phal in the highest humidity you can provide. Also, make sure there is nice air circulation, along with the humidity, otherwise you r asking for another kind of death
But u don't need a hurricane either
. You will want some good warmth, (not Hot!) around 83°-89°F (daytime). Fyi, if it's too warm/hot, and the humidity is low, the orchid will lose water, instead of retaining it, so watch for that as well.
I've also heard to put an ailing orchid in
slightly less light, as that will help it to not lose so much water (thru the leaves), b/c it won't perform as much photosynthesis as it would with normal light. But, I can't recall if I have ever heard a confirmation on whether this is a fact or not.
Edit: The above poster beat me to it! That post wasn't there before
Well, sorry for the repeat! Lol