I went with an RBI and am very happy with it. Along with the RHP I added two Zoomed heat pads (I know overkill) underneath the bottom of the RBI where the hides go, one on each side. The whole RBI is sitting on four rubber feet that I got from Home depot, this provides about a ½ in. space for air circulation required for the heat pads. I made some small holes in the back of the RBI, just big enough for the probes to pass through, with a Dremal tool, it was quick and easy. I found some felt fabric on line that is very similar to reptile carpet and stands up pretty well to the washer and dryer. I cut this to size for the bottom of the RBI, I made some small holes just big enough to pass the sensor on the probe end through to hold them where I want them with the wires hidden underneath the fabric and passed through the back wall of the RBI. One probe under the hot hide, one under the cool hide and one on the floor under the RHP to control my ambient temp. Then I add a thin layer of substrate. I am using a Herpstat Pro to control the temps as it gives me four different channels to play with (again, overkill).
My hot hide is 90° my cool hide is 81° and ambient is low 80’s.
I was using aspen for about three weeks. I was having problems with the humidity dropping off way to fast and the dust was incredible. After thinking about this for a while it dawned on me that MJ has not had a poop the whole time that I was using the aspen. Before the aspen she pooped almost weekly. Last week she did pass urates twice. Just wondering if anybody had any thoughts on this. This week I decided to try some cypress mulch, much less dust.