It seem I go through a lot of wood. I have a GOSM (propane of course) and I use the smoke box that came w/it. It seems like I have to put chunks in about every 1-1 1/2 hours. They turn black like coal and seem to quit smoking. Should I get a different box, or is this normal? Even when I use chips they seem to do the same thing. Are the chips supposed to turn to ash before changing them? I use hickory,cherry,apple and mesquite with the same results from all.