The important part is that you understand WHY the medium mix works, Erin. I've included a link below... it's the 6th posting on the subject, and includes some updated medium recipes. Please read it before you begin mixing ingredients.

It's important that all the ingredients you use are approximately the same size. The idea is to create a medium that water can pass through, leaving enough moisture for the plant to use, but not too much so it has to sit in that moisture.

My recipe includes the following:

1 part uncomposted pine or fir bark (1/8 to 1/4 inch approx. size pieces)
1 part Turface
1 part crushed granite

To this I add some perlite, a handful or two of Schultz's potting mix, and a handful or two of vermiculite.

I sort of eyeball the additions as I mix them in... you get to know what looks and feels right. The important thing is that most of the ingredients have about the same size pieces.

I looked into orchid bark, but the pieces are too big... it should be more like Schultz's Soil Conditioner, which are very small pieces of pine bark.

I'm not sure how important the lime is, but I'm sure it does serve a purpose. I think if you read all the questions and responses in the link below, this question is answered.

My thought is that all purpose soil is too fine and decomposed to use more than a tiny bit... and the orchid bark pieces would be too large and would need to be ground up somehow. If you have a chipper/shredder, you'd be in business!

Give the link a read before mixing your medium... I think you'll find some tips and ideas, and have a better understanding of why you're doing this.

I haven't had a full cup of coffee yet, so I'm not sure how much sense I'm making right now! :-)

Here is a link that might be useful: Container Soils - Water Movement & Retention VI