Question on Temp

I have a 20 gallon and 10 gallon aquarium with a UTH on both. on the 20 gallon I also have a 60 watt light bulb (one for night and day). According to the temp on the side of the cage it is 86 in the basking area. When I put the same thermometer on the ground of the cage it reads 105. Is it ok for it to be this hot? Much thanks, Chris.

The temp on the ground is what is important and your is too hot. Do you have the undertank heater on a thermostat or a rheostat? If not you need to get one asap. You can also try turning off the light. You want the surface temp to be between 86 and 92. I would also recommend a digital thermometer with a probe. You can get these at most target or walmart type stores. Place the probe directly above the heat source on the substrate.

Yes, the ground temperature is what matters. You don't, so I believe, have to have an undertank heater; you could use just the bulb (especially if you have a Leo that likes to dig!). The important thing is that they have a thermostat to regulate temperature, of course this needs to be calibrated to achieve the right temperature. I have a thermometer which measures the centre gradient of 82F in my tank (that is the temperature right in the middle, just above the substrate). The probe is placed just underneath this, right above the substrate to give the correct temperature reading. This gives a slightly hotter end (under the basking light) and a cooler end. I place the humid hide more towards the hot end and a log running from the cool end into the hot end. I also place a normal rock in the vicinity of the bulb (though not directly under it) which warms up during the day, which Amos then warms up on when she comes out at night.

Hope this helps

SIMON