HCA: Hermit Crab Association

Hey guys new hermit crab owner here. Its been a bit colder the last couple days here and i have found that my temperature is dropping below 20 Degrees Celsius (68 Fahrenheit). The humidity wasn't too bad sitting at roughly 78-85% but i have added play sand to the tank and it now sits at 99% whereas before i was using aquarium sand which was a dryer substance. The tank is in the laundry which i know is more of a humid room but it also gets cold when nothing is running. I currently have a 10W URS ultimate heat matt (small) that sits under the tank, which worked ok when i only had a small layer of sand in the tank but im wondering how that gets affected when i have a decent layer of sand on top. I was considering light/ heat lamp as an alternative but all the pet shops i have asked have said its not a good idea. Thoughts?

PS. Substrate is mixed with a little aquarium sand as i didn't want to do a complete change just yet and i am going to add Eco Earth coconut fiber as well but have to purchase online as dont have it in pet stores. Plants are also fake if that makes any difference.
Also i have a 28 gallon terrarium.

Elli wrote:Hey guys new hermit crab owner here. Its been a bit colder the last couple days here and i have found that my temperature is dropping below 20 Degrees Celsius (68 Fahrenheit). The humidity wasn't too bad sitting at roughly 78-85% but i have added play sand to the tank and it now sits at 99% whereas before i was using aquarium sand which was a dryer substance. The tank is in the laundry which i know is more of a humid room but it also gets cold when nothing is running. I currently have a 10W URS ultimate heat matt (small) that sits under the tank, which worked ok when i only had a small layer of sand in the tank but im wondering how that gets affected when i have a decent layer of sand on top. I was considering light/ heat lamp as an alternative but all the pet shops i have asked have said its not a good idea. Thoughts?

PS. Substrate is mixed with a little aquarium sand as i didn't want to do a complete change just yet and i am going to add Eco Earth coconut fiber as well but have to purchase online as dont have it in pet stores. Plants are also fake if that makes any difference.
Also i have a 28 gallon terrarium.

Hi there!

How deep is your substrate? It should be 6" deep, or 3x the height of your biggest crab.
Your uth (under the tank heater) should always be placed on the side or back of your aquarium, above the substrate line, never on the bottom. Placing it on the bottom will heat the sand, and can be dangerous to digging crabbies. The goal is to heat the air, which is why it should be on the sides or back. If the mat you have is one that has adhesive, it is not safe to remove and reuse it. I don't use an uth as my house is warm enough, but many crabbers prefer an Ultratherm mat. Don't go by the gallons an uth can heat when purchasing a mat, just get one that will cover the entire area of the sides and/or back of the tank. You can always switch the heaters off if it gets too warm. Many of us don't use heat lamps because they can drastically lower humidity.
I hope this helps some!
Also, your images didn't come through. You can download the Tapatalk app to post pics, or create a link on a pic sharing page and post the link here.

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What she said! ^^^

Here is a guide Fleabag helped me with last year. It a different size tank, but the same directions should apply to any tank. Also Reflectix is so much easier to use as insulation compared to in the tutorial.
viewtopic.php?f=26&t=119297

Thanks guys the substrate is just under 6 inches at its highest point. Th heat matt i currently have as in image is small and was ok for a smaller setup I started with but I now have a larger setup so it only takes up a smaller section of the back. Temp dropped all the way to 14 degrees Celsius this morning . Will go today and get a bigger one, I do have fake plastic plants on the back would the heat mats affect those?
Thank you for the link I will have a look today.

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Humidity and temperature are linked, due to how much moisture air can hold at different temps. As your heat goes back up with the larger mat, the humidity will drop down again.

Elli wrote: ↑

Sat Apr 04, 2020 3:40 pm

I thought that was some kind of cool humanoid climbing structure, but turns out it was just you

Harry Wang wrote:
I thought that was some kind of cool humanoid climbing structure, but turns out it was just you

Haha darn reflective glass. Makes it hard to take a decent picture.

Also I want to thank you guys for the advice I am constantly looking through the forums for ideas and advice. As in images i have gone out and bought a 60 watt infra red (heat) and daylight 2.0 UVB (no heat) as per pet store advice. i love the idea of the heat mats but in Australia its really hard to find good ones without purchasing online and my temp was not moving above 15 degrees Celcius (unfortunately only place I can put the tank is in the laundry which is very cold during days like we are having today which is cold, windy and raining). So far it's going well, as most have mentioned humidity took a dive and quickly, I have put an extra bowl of dechlorinated water under the heat lamp and covered the ventilation areas with cling wrap which seems to be keeping things really nice for now and has prevented humidity from plummeting but will keep a close eye on it.

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Elli wrote:Haha darn reflective glass. Makes it hard to take a decent picture.

Also I want to thank you guys for the advice I am constantly looking through the forums for ideas and advice. As in images i have gone out and bought a 60 watt infra red (heat) and daylight 2.0 UVB (no heat) as per pet store advice. i love the idea of the heat mats but in Australia its really hard to find good ones without purchasing online and my temp was not moving above 15 degrees Celcius (unfortunately only place I can put the tank is in the laundry which is very cold during days like we are having today which is cold, windy and raining). So far it's going well, as most have mentioned humidity took a dive and quickly, I have put an extra bowl of dechlorinated water under the heat lamp and covered the ventilation areas with cling wrap which seems to be keeping things really nice for now and has prevented humidity from plummeting but will keep a close eye on it.

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Glad you're getting things warmed up!
Just be careful that the crabbies can't get to the heat lamp if it's inside the tank. They are great climbers, and wouldn't want to see them burn their little legs on the bulbs.

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Harry Wang wrote: ↑

Sat Apr 04, 2020 6:57 pm

I thought that was some kind of cool humanoid climbing structure, but turns out it was just you