Probably not an issue since this is a relatively new tank. The bubbles are caused by denitrification and are gas escaping from the lower regions of the sand bed.
The best dource for detrivores is from an established tank via a cup or two of sand. Aside from that you could spend a bundle on one of those detrivore kits I've seen at Inland Aquatics or GARF. From what I've heard you get a very small quantity of critters for a large quantity of money but that may be your only option.