HCA: Hermit Crab Association

Hi everyone! I'm finishing up a new build for a 29g tank - my 4 new hermies are currently in a 10g and I'm so anxious and excited to get them moved over.

I bought a digital temperature and humidity sensor by Acu-Rite. I followed the instructions on here about calibrating (teaspoon of damp table salt, put it in a tupperware container with the sensor, and then bagged it to try to make sure it was air tight) but I'm not sure what number I should go with for the humidity and how I should be adjusting. When I first put the salt in with the sensor, at around 11pm Thursday night, it was at 43%. When I woke up it showed 67% but said that the highest it had gotten overnight was 72%. We then went out of town over the weekend and I kept it in the bag because I completely forgot. When we got home today, it still shows 72%. So is that the number I should go with? I don't think there's a way to actually adjust it and essentially "zero it out" since it's digital.... so should I just know in my head that since it was 3% off from the ideal 75% with table salt, that I need to make sure the humidity number on the sensor once in the tank is no lower than 83% (knowing I need a minimum of 80%)?

Also, I can't seem to keep the temp where it needs to be. The place where the new 29g tank will be set up is closer to a window and in a room with a lot more natural light so I'm hoping that will help with the temperature, but I'm going to buy a UTH just in case. What are the favorites? What size do I need for a 29g? Should I keep it plugged in 24/7 or get a timer so maybe it cools a bit at night to mimic natural temp fluctuations?

Thanks!

All I know about calibrating a hygrometer I learned from the HCA care sheet:

viewtopic.php?f=26&t=92540

There is not a way to 'zero' the digital hygrometer, so you just need to note the difference. What you said about being 3% off and knowing you need 83% is correct.

You want to get a UTH that you can insulate over if you need to. Get an Ultratherm, or one from the Bean Farm. Go by size measurements, not by the size of tank it says it will heat. You want one to cover as much of the area above the sub as you can. Someone else can help with exact dimensions, as I've never had a 29 LOL. A thermostat would be perfect, to keep the temps more even.

curlysister wrote: ↑

Sun Aug 02, 2020 2:54 pm

All I know about calibrating a hygrometer I learned from the HCA care sheet:

viewtopic.php?f=26&t=92540

There is not a way to 'zero' the digital hygrometer, so you just need to note the difference. What you said about being 3% off and knowing you need 83% is correct.

You want to get a UTH that you can insulate over if you need to. Get an Ultratherm, or one from the Bean Farm. Go by size measurements, not by the size of tank it says it will heat. You want one to cover as much of the area above the sub as you can. Someone else can help with exact dimensions, as I've never had a 29 LOL. A thermostat would be perfect, to keep the temps more even.

Thank you for confirming my not-so-math-savvy brain was thinking about the humidity percentages correctly lol. I'm online now looking at some UTHs and will order one. I also decided I'm going to add in bubblers to my water pools to help with the humidity, so on the hunt for those things too

One question based on your response - what do you mean about getting a UTH that I can insulate over if I need to? What does that mean? What would I insulate it with and how do I know if I need to do that?

Thanks again!

The UTH's that have a sticky side (ie ZooMed) can not be insulated over. If you have trouble getting your heat up enough, you can add some insulation to help keep the heat from the UTH from escaping out the back side of it. You'll know if you need to insulate it, depending on what temp your tank is. Some people use a product like Reflectix, or a car windsheild heat reflector thing, some people wrap cardboard with tinfoil (that's what I did LOL).