HCA: Hermit Crab Association

For the past few days I've been setting up a 10 gallon in hopes of getting 2-3 small crabs. Everything is in. Water dishes, substrate, etc. I'm using a reptitherm uth on the back side. I believe its their medium or medium large model. Average house temperature is around 70-75 f. Tank temperature is 73-79. For the past half of a day I haven't gotten a reading higher than 77. Currently stuck in a 73-75 loop.

What should I do? I can't use a heat lamp because I got a screen lid + plastic wrap on top (which really helped with my humidity issue) My humidity is really good rn, looking at 85-90% Putting a towel on top hasn't helped with the temperature much. Im thinking about getting a smaller uth and putting that on the back as well but I don't want to accidentally stress crack the tank.

Sounds like you are off to a great start! You can for sure use multiple UTH's (I have two on the back and one on each side of my tank). Or you can add insulation. Is the Reptitherm sticky, or is it attached with tape?

You are off to a good start like curly said! That's always a plus. If you could get a glass lid that could possibly help you get your tank up those few degrees. Reptitherms CAN NOT be covered with insulation. you can however insulate around them with aluminum wrapped cardboard.

Also where is your thermometer? Your tank will always vary in temperature based on its location in the tank. You want an average temperature. A crab will regulate their body temp by moving to a comfortable area to warm up or cool down. It's ok to have cooler spots as long as you have warmer areas too. My 75 gallon can vary 15 + degrees based on where I place the thermometer. Next to the UTH it can read 98, near the front glass at sub level mid 70's. Up high in the 80's.

Move your thermometer around every 10-15 minutes and check what it reads. That way you can get an average reading based on several readings.

Moved the thermometer closer to the uth and I got 77-81, front glass gets me 72-77, normally 75, the uth is sticky so I've put it on the back.

Thanks Motor! I can never keep track of what can be insulated over top and what can't!
Adding the insulation around it would help with the heat. You don't need it much, if any, warmer.