I agree regarding Miracle Gro orchid mix. Never tried it but it looks like sure death for epiphytes.
If you can't find something like Better Gro (another brand that I think is carried by Lowe's), you can make your own with a sack of "reptile bark" from the pet store with added perlite and charcoal (also available at Lowe's/HD). Probably equal parts of each would make a good loose mixture.
You can surely find good mixtures online, but shipping can be more than the product!
Have fun - Nancy

Show season has started in Michigan, so you will have a couple of chances to get good mixes. The next one is the end of this month at Frederik Meijer Gardens. We have a vendor who will have lots of choices of mixes coming. Then Lansing has their show in Feb, and Ann Arbor in March. Then Detroit and Traverse City. All shows are free, and I suspect all of them will have someone selling orchid bark, coconut husk, S/H stuff, you name it. Plus, if you need advice they are all so nice. So pick one and come on down!

Thank You Lisa for reminding me of the Orchid show at Meijer Gardens! I went today and bought two beautiful bags of potting mix for Phals. only $5 each. I am so happy just looking at the mix of fir bark, charcoal, forest humus, sponge roc, and sphagnum in my bags. Thanks again for all your help :)