Orchid bark, cypress mulch, coco coir, peatmoss are all good. Peatmoss is a bit difficult to get it all wet/moist....but once you have it nicely moistened, it makes a nice clean substrate. I mixed a combo of all of the above and it makes a nice clean substrate.
So bottom line, it won't hurt at all, just make sure that it is 100% peatmoss, with no additives or fertilizers, etc.