I have a Backwoods smoker and have had the same problems you're having. With my Backwoods it is almost impossible to hold the temps down without water. Also, I found that I had to use a maze in addition to the water. After these two techniques were combined I was able to hold temps very well. I also use an Auber system with a 6 cfm fan. I used three bricks and made an upside down "U" shaped maze. When I have time I will have a removable steel maze fabricated which will give me some additional space in the firebox and increase my burn time before I need to add charcoal. I hope this helps solve your problem, as I know how frustrating it can be to see the temps keep rising past your set point time after time!