I'm using a 100 watt for my 50 gallon tank.. and have never had problems maintaining a nice and toasty temperature. But with the air conditioning going it's getting challenging.
Right now, we border around the 81-83 degree range.
I know optimally, it should be at 85-88...
But what can I do? If I upgrade to a 150 watt bulb, do you think that'll be too big of a jump in wattage and therefore make the tank way too hot?
I have a heating pad under the tank to help with humidity.. but it's not doing anything for my temps. What else can I try?

I'm not sure you might try covering part of the tank top. Is the tank close to the ac vent, can you redirect it?

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MARSHA

:D I'm smiling because I have no idea whats going on!

nope, not close to the air conditioning at all. But it's in my room, which is in the basement which is colder to begin with!! (I sleep under 3 blankets all the time!!) I have a 24 inch light and the basking light and I have a damp towel covering the rest of the screen top.

I think you should try a higher wattage light, you can buy a dimmer if it gets too hot.

that's a good idea! I never thought of that..

And when the air conditioning goes off and you're not at home to adjust the dimmer your animals will cook to death =(

I don't know what kind of lamp you are using but you should get a thermostat and a Ceramic Heat Emitter if you're using that lamp to heat. Regular light bulbs produce heat as a byproduct of energy to light conversion. CHEs on the other hand produce only heat being much more efficient.
A thermostat ensures your animals have safe temps all the time.

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Wish list: Blue Tongue Skinks and Uruplatus =)

i've never even heard of a thermostat to regulate the temp inside the tank! I gotta look into this!
I'm using just a regular Exo-Terra Basking Bulb right now.. but I have to look this!

In some basic models like this one you place the entire thing inside the enclosure. The better ones have a probe (like your digital thermometers) and only the probe goes inside the enclosure.

Here's a couple of pages to start with:
http://www.zoomed.com/html/ceramic_heat_emitters.php
http://www.zoomed.com/html/thermostats.php

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Wish list: Blue Tongue Skinks and Uruplatus =)