Postby JWSR » Fri Jul 20, 2007 8:40 am
If you're going to be using an analog thermometer like I see on the back wall of your enclosure, you need to move it down to nearly touching the substrate. Right now, you are measuring the temp of that one side way up near the top where all the heat rises to. You need to measure where the skink lives, down at the bottom. There will probably be about an 8 degree difference. Also, these thermometers can be as much as 3 to 8 degrees off unless you calibrate them before use. I use them for ambient temperature only in the middle of the cage. There's nothing better, in my opinion, than the dual probe digital thermometer from BigAppleHerp.com One probe lays on the substrate on the hot side and one on the cool side. The readout unit sits outside showing both digital readings. It really makes temp management a lot easier.
On another note; a rheostat (dimmer switch) does nothing for maintaining a constant reliable temperature. It only providea a constant wattage to the heating element/light bulb. This means that if your room temp rises, so does the cage temp. The same if it lowers. A thermostat is what you need to keep things right.
I'll simplify a heat management system for you. Or, at least I'll try...........
For that enclosure, which I believe is the same 65 gal. I've got for Irwin (as soon as he's big enough to move in) you will want one bulb, spot or flood diretly above his basking rock or log. Wattage is something you might have to experiment with. You'll want a wattage that will get the basking rock about right, while not over heating the warm end of the cage. This is where a digital TempGun is great to have. You want to get the basking surface to about 95 to 100 degrees. But, at the same time, this light is going to be adding some heat to the entire warm side of the cage. If the light warms the basking rock just right, but gets that side of the cage too hot, you need to lower the wattage of the bulb and raise the height of the basking rock. You want to have another dome near your light dome. But, in this one, have a 150 watt. ceramic heating element on a thermostat with the sensor lying on the warm side substrate. This will regulate your overall warm side temp. Turn up the thermostat until the temp gets right on that side of the cage, then turn it back just until it clicks off, then you're set and ready to check the cool side. 9 times out of 10, it should be just about right. If too cool, another ceramic element on a thermostat over there set at about 80 will do the trick. All bulbs and elements plugged into a good timer, on 12 to 14, and off 10 to 12 and you're set.
You will usually find that once you get that pesky basking rock right, that it will usually stay within about 3 degrees up or down. The main temps you want to be fairly critical of are left and right substrate temps, where your bluey lives, except when basking.
I hope I've been of some help and haven't confused you further.
Good luck with your new baby!
I wish I could get this right... 
I mounted the basking light up about 4 1/2 inches above the terrarium and that solved the problem! That simple. Sometimes I make things more complicated than they actually are... 
