Orchid bark and Repti Bark are both fir bark. Fir bark particles have a nice chunky shape, and usually come very well graded with little sapwood. Pine bark is usually bought as large bags of mulch. It has a flatter shape, and can vary significantly in particle size, amount of sapwood, and state of decomposition.

Cypress mulch has been found to be allelopathic towards plants grown in it, so I'd avoid that. I've never heard of spruce bark being sold as mulch, or used for container growing, so I can't say whether it would be a good choice. Fir and pine bark are definitely safe choices, and most people can find one or the other in their area. Look closely at the particle size, amount of sapwood (light colored splinters against the darker bark), and state of decomposition when buying. I've bought a number of bags of pine bark mulch only to find that they were not appropriate when I got home and opened them up.

Reptibark works well but finer grades of orchid bark are usually only available from orchid nurseries. Check out the nurseries near you by searching at The Orchid House under Orchid supplies. Also RepotMe.com might be another place to look.
When using bark be sure to soak it first or the potting mix will dry out too quickly at first and stress the plant. Even soaking overnight is fine and add a drop of liquid dish soap to help speed things up.

Mike

I did call one of our 4 nurseries, she said that they carried a orchid soil mix that has bark,peat moss, red lava rock and a few other ingredients that I don't remember. Would this work? Maybe I should stick to looking for the smaller bark I don't how the orchid soil mixture would work and I know that the other mix with grit, turface and bark works great. I shouldn't mess with something that works even with the bigger pieces of bark Thanks so much for the answers I got.
Ann,So Ut

What the thing you're growing is Cypress? Then wouldn't it be okay to use Cypress bark?

I have no problem using "cypress blend" bark (the way they market it-the blend thing). I like to use Pine bark fines...much smaller that those big nuggets in regular mulch.