So I started trying to heat my tank with a 60 than a 75 watt bulb, as repliers to my last thread recommended. Those weren't hot enough, so I tried with a 100 watt bulb. This one has only gotten the cool side of the tank to about 72 degrees (Fahrenheit.) I'm not sure about the basking spot's temp right now, but it feels about 80. Again, I need baby beardie temps for my tank.
I'm using a digital thermometer with a probe and I have a porcelain lamp for the basking light. The tank's a 20 gallon long and I'm using newspaper as a substrate, if that affects anything. Normal temperatures in my house right now are about 65 degrees.
Is there any reason the tank's not getting enough heat? Or should I just keep upping the bulb wattage?
Instead of increasing the wattage, you might consider getting another lamp. You could get a CHE (ceramic heat emitter) bulb, which doesn't give off any light. You could leave it on during the night too to keep up the temps then.