Here's a link to a product I've been using since last October. I never treated it in any way. I've got mites only once in 6 months, but it was weeks after a bedding change so I don't believe they actually came from the mulch. I think it's a great product especially when combined with some coco fiber. It holds humidity pretty well and is pleasing to the eye. It is made for landscaping so you gotta pick out a few big pieces of wood, other than that I have no complaints. And you can't be the price. It does however come in a 35+ lb bag so you'll need a BIG(40 gallonish) plastic container to hold the stuff not in use.

http://www.lowes.com/pd_92889-76450-...ductId=3467633