Maybe! Where are you in the USA and what sort of orchid are you going to repot?

There are many materials that can be used in potting mixes.

There is a discussion hereabouts about using untreated pine bark as a material. What is fir mulch?

In ancient times Fir Bark was used a a potting material and it was good.

I have a Phal I am pretty sure. I actually meant fir bark, and I did a quick google search and saw it was recommended for orchids. I got it like a month ago and it was doing well and all the flowers were out, more were growing too and getting larger.. but all of a sudden a few of the larger petals started falling off so it worried me. Also, all of the large green leaves go strait down over the container it is in. I still have it in the pot I bought it with. I took a look at the roots at the bottom and they are coming out of the drainage holes and are squishy and gross, so I am pretty sure I need to repot it and I am wondering the best substrate to use. I am new to planting and I just started indoor Orchids and succulents.

I live in Northeast Ohio

Do not use "Sweet Peat", I know what that stuff is. Fir bark is a very good potting media.

I used fir bark but still the flowers are wilting and falling off =( what am i doing wrong?? unless this is normal.. fall is soon approaching, but it is an indoor plant.

The flowers should last several months after opening in good growing conditions. Perhaps the flowers were due to die. As for "What am I doing wrong!" perhaps nothing, Perhaps you are overwatering, Perhaps the the pot you used is too big. Maybe there is something unsuitable about the place where you have the plant.
Did you find some complete growing instructions on the net written for growing conditions in the Northern USA?
Maybe you had it outside when it might be best inside all year in your Climate.