HCA: Hermit Crab Association

I am planing on getting UTH for my twenty gallon long tank and was wondering if I should get the one that says 10-20gl or 30-40gl. Also depending on size should I mount it on the side or bottom. Thanks

p.s. For those wondering i am using a fish heater in a quart jar with water for heat works well just gives off a lot of moisture.

Edit: The average temp of my room in summer is between 70-75 and in winter 60 or a little above.

get these, much better and safer and can be taken off to add to another tank
http://www.reptilebasics.com/index.php? ... rm&x=0&y=0

If you're not able to get the UltraTherm for a 20 gal long, honestly I would get the 30-40 gal size UTH (side or back mount). Not sure what the temp in your house usually is? I have a 20long, my house temp is pretty much 70F all year long, I put the 30-40gal size one on the back left side of my tank, & I have a heavy towel draped over the back of the tank,kind of as an insulator & my day temp is 79-83F. At night I roll up the towel part way up the back and night temp is 77-78F. If my temp dips below that then no one comes out

I brought a UTH, it was a dissapointment. It hardly affected the tank at all. I emailed the company and they said that's what they are designed to do. I had a lot more luck with a heat lamp and a ceramic bulb.

eloise13- what size tank do you have and what is the wattage of the UTH? Also, where is the UTH placed (back, side, underneath etc)?

What brand of UTH did you buy?

It is a 10x11 exoterrra, 16 watts. it is the "desert" model. my tank is 42 gallons. it's on the side. I know it's a bit small for my tank, but it wasn't doing anything, at all. I had my thermometer right next to it and after four hours, it hadn't even raised that area by one degree. At one point, I took the thermometer out of the tank and left it in my room for a while, and my room was actually warmer then the tank. I know that UTH don't get hot to the touch, but it took a hour before there was a difference between the normal glass and the UTH itself. I know UTHs, aren't very strong, but that's just silly! My ceramic bulb started to heat up straight away.

I never used any other UTH than ultratherms,you can insulate it in the back to bump up the temp. Not sure that a 10x11 is big enough for a 42 gal.Can it be returned?Are the "desert" ones good to use on crabs?

I haven't asked about returning it yet, I don't think it can because they are the type of ones that break if removed.


Desert ones produce dry heat. The rainforest ones produce humid heat, but are not as hot. IIRC, the desert one is supposed raise the temp by 10 degrees and increase humidity by 5%, while the rainforest one increases heat by 5 degrees and increases the humidity by 40%

It is a 10x11 exoterrra, 16 watts. it is the "desert" model. my tank is 42 gallons.

I have a ZooMed one that is 16watts, recommended for 30-40 gal tanks but I use that one on my 20gal and having to keep a heavy towel draped over it I wish I had bought the 24 watt for 50-60 gal. I don’t know why they recommend such low wattage, if you go by the recommended size you’re lucky it raises the temp by a few degrees, smh. I need to raise by a good 10-12 degrees, which sounds like you’re in the same boat.

I had my thermometer right next to it and after four hours, it hadn't even raised that area by one degree.

I have found that it does take a while to heat up, a couple of days before the temp stabilizes. I did a deep clean earlier this year and when I plugged it back in, by the time the glass, all items in the tank, substrate etc. warmed up it was a good 2-3 days. Because, really, all the stuff in the tank & the tank glass has to get warmed up too. I would let it run a few days, try draping a heavy cotton towel over the uth side, I roll up the towel so the roll part sits on top of the tank so the whole top isn’t covered (though you can probably cover the top with the towel too and it will maybe help keep heat & humidity in)

My ceramic bulb started to heat up straight away

Did your humidity drop?
I haven’t used ceramic heat emitters, but I did try one of those full spectrum day bulbs (25watts, I think) but I could not maintain the humidity since I could not keep the screen lid covered with anything for fear that I would melt it and cause a fire etc. (yeah, I’m a little paranoid, LOL!)

IBlab crab- Are the "desert" ones good to use on crabs
eloise13- Desert ones produce dry heat. The rainforest ones produce humid heat, but are not as hot. IIRC, the desert one is supposed raise the temp by 10 degrees and increase humidity by 5%, while the rainforest one increases heat by 5 degrees and increases the humidity by 40%

I don’t see how the “desert” could be any different than the “rainforest” ones that Exo-Terra puts out. 16 watts is 16 watts, I don’t see how a heat mat placed on the outside of a tank can raise humidity on one type and not the other. If your substrate is moist then the warmth from the uth can bump the humidity (put a uth on the bottom of a tank and sit a water bowl over it, the moisture in the tank will increase) but if you have a dry environment how can it increase humidity if there is no moisture in the tank to begin with? Put dry sand in a tank and put a uth on, where is the extra moisture coming from? I don’t know, maybe its me, but it doesn’t make sense. I think I’ll email Exo-Terra….
Not trying to start an argument or anything, just trying to make sense of it.

IBlab- I never used any other UTH than ultratherms

I have heard really great things about them, and when I get another UTH, that is what I’m getting

I haven't asked about returning it yet, I don't think it can because they are the type of ones that break if removed.

I have removed a few of mine numerous times and no damage You have to be careful & do it slowly, and it comes off easier if its slightly warm, unplug it and let it cool down a little but not all the way and it comes right off, just pull slowly, and they stay sticky too. However the longer they are on the tank the tougher it will be to remove and still keep the sticky part. I recently tried to swipe my hubby’s 29gal tank that he has a corn snake in and the uth is on the bottom and has been on there for about 7-8 years and when I peeled a corner the sticky part stayed on the glass. Dang! LOL!

But, yeah I would first locate a store with the correct size UTH that you need (probably at least a 24watt one maybe more since your winter temps are around 60F) and then try to return the one you bought.