Can I Move A UTH?

Guest · Post by **Guest** » Sat Feb 21, 2009 5:29 pm

A very generous former crabber gave me her 10g tank about a month ago. My pp's live there now. It's a great tank, it even came with a UTH! It's on the back towards the bottom. The problem is that my sand gets super dry right there. I think more heat goes in to that small area of sand that the tank as a whole. And of course, my crabbies like to dig there since it's extra warm. I sometimes pour some water on the sides and mix it a little, but I don't want to make water pockets, or disturb crabs who are dug down there.

So my question is: can I move a UTH? I'd like to put it on the end of the tank about half way up. My other tank does great for heat and humidity with it there. Any suggestions? Thanks!

Guest · Post by **Guest** » Sat Feb 21, 2009 6:23 pm

they can be moved, but may not stick as well. you can put it on the side. I have them on the side as well as the bottom. a little hint (electrical tape will work if the uth decides not to stick to well) i have had to remove mine a couple of times some stick back good, some don't.

Guest · Post by **Guest** » Sat Feb 21, 2009 6:27 pm

thanks! Good to know.

So just a little electrical tape around the edges?

Guest · Post by **Guest** » Sat Feb 21, 2009 6:30 pm

yea! thats what i did with one of mine, i had to check from time to time and push the tape back down, but it worked.

Post by **JediMasterThrash** » Sat Feb 21, 2009 7:44 pm

Read my post in this thread about UTH:

http://www.hermitcrabassociation.com/ph ... hp?t=11370&

And here's my post about Reattaching UTHs (which doesn't seem to appear in the archives

UTH's work by transferring heat energy to matter they are in contact with.

When a UTH is attached to the glass bottom of a tank via its original thermal adhesive coating, the heat energy transfers directly through the glass (that the UTH is attached to) and through the sand that rests on the glass.

When a UTH is re-attached or only taped on the sides, the heat energy transfers first through air pockets, and then to the glass, and then to the sand that rests on the glass.

Temperature is a measure of the kenetic energy of atoms. Transferring W watts of heat energy through glass and sand raises the temperature of the sand more than transferring W watts of energy through air raises the temperature of the air.

The reason for that is the difference in specific heat of the matter. Air has a specific heat of .025, while wet sand is 1.5 and glass is 1.38.

This means that an UTH will raise the temperature of the air trapped between the UTH and the tank 50 times less effectively than it reaises the temperature of wet sand it is in contact with.

So I don't recommend removing a UTH, or trying to re-use it, unless you can recreate the original bond between the UTH and the glass.

eregel · Post by **eregel** » Sun Feb 22, 2009 4:58 pm

I've moved UTHs several times, with no problem at all. I also have been known to attach UTHs to the background on my tat's rather than directly to the glass. They still work that way, but reading JMT's post makes me reconsider - might be slightly less efficient than it could be.

Guest · Post by **Guest** » Wed Feb 25, 2009 4:52 pm

This means that an UTH will raise the temperature of the air trapped between the UTH and the tank 50 times less effectively than it reaises the temperature of wet sand it is in contact with.

that is really interesting...... I am sure this is why my original uth was not working well.. I stuck it on very very loosely because I thought I might have to remove it, and didn't want to break it when I did. so I didn't make a really firm seal to the glass. .... wow.. now I have to give some thought to how to get these more firmly sealed again...... *thinking*

thank you, well this clears up a lot of mystery!

Guest · Post by **Guest** » Thu Mar 12, 2009 1:34 pm

i didn't think you were supposed to get the glass next to the UTH wet (wet sand) because it could crack it ( unless your watching the temperature of water your putting next to it i guess) just thought you might want to know since someone gave it to you and you didn't get to read the warnings that came with it

nora · Post by **nora** » Tue May 19, 2009 12:00 am

I have found that my UTH that uses the Flexwatt system can be reatttached with out any loss of heating capacity. :)
nora