I also had a few more questions

I've noticed the last week the cool end of the tanks temp has dropped from 75 to around 70. The first few weeks it stayed right around 75/76. Nothing has changed in my house and my room is actually very warm. Not sure what's up .

I bought the cheap thermometer from Petco which was like 8 dollars. This payday I'm going to buy a better one just to see if maybe the readings are in accurate.

But if it's not a problem with that what would be a good step to take? Buy a heat mat? Get a thermostat?

Also I noticed the warm end is only like 81/82. I'm just using the heat lamp that the other owners gave me. Should I look into another lamp? And if so is there any recommendations?