Tub heating quandary: concave tub + flat UTH = ?

[artgecko]

hello guys,
I wasn't sure where to put this, so please move if needed.
As many of you know, I am preparing for a new boa. I'm putting him in a tub and am using this tub, the 110 qt. steralite. This tub's measurements are 34 5/8 x 18 3/4 x 12. I am planning on using a UTH for the hotspot and heat lamp (outside tub on cool end) for ambient temps.

My problem is this... I have this ultratherm heat mat , which should be perfect at 11' x 17" to heat 1/3 of the tub bottom.. The only issue is, the heat mat is slightly larger than that and the tub bottom is slightly concave.

Last night I got the tub setup. I attached the UTH to the surface the tub would be on, setup the probe and thermostat, etc. With the UTH attached to the table, the bottom of the tub did not come in contact with the UTH except on the edges, the center part of the tub was at least 1/2 - 3/4" above the UTH and it did not seem to heat very efficiently at all (I had it set initially to 91f and my thermometer probe was reading 80 in the tub over the UTH). After trying it at a higher setting (95) and still not getting temp readings in the 90's, I decided to attach the UTH to the tub bottom instead (the concave part).. The only issue with this arrangement is that the mat would need to be slightly bent / curved to match the concave curve in the tub, because it is too large to be seated solely where the tub is higher. With that setup, I got better readings, but very spotty (was using my temp gun).. Some areas of the tub over the mat read 93, 2 inches away, read 88, 83,etc.

I'm not sure if bending the UTH like in the current setup would cause a short down the road or is causing the spotty temp readings, but I'm also not sure I want to crank up the UTH to, like 99, if attached to the table in an attempt to heat the tub above it.. Neither of these seem like ideal situations to me.

I'm considering ordering a smaller UTH that would fit within the raised area of the tub and adhering it there, but again, I'd hate to not use the UTH I already ordered for this project just due to it being too big, and this would push back my setup date and mean that I'd have to wait longer to get my snake shipped.

If you guys have any input I'd greatly appreciate it.. I did not anticipate that this project would be so difficult.

Thanks!
Artgecko

[PitOnTheProwl]

I'm also not sure I want to crank up the UTH to, like 99, if attached to the table in an attempt to heat the tub above it..

Why?
This is the point of a non contact thermometer and a thermostat.
As long as the area your reptile can touch is not hot enough to burn them you are good.
This is why those of us with balls have to set our stats higher in our racks to get the temps we want.

[artgecko]

pitontheprowl- If this is not dangerous to the snake...i.e. if setting it that high won't cause other issues or overheating, than that is fine with me. Is it better to NOT have the tub bottom in contact with the UTH and for the UTH to just heat the air over it which then heats the tub? If this is safer, than I don't have a problem with it.

[PitOnTheProwl]

Your concern is with the surface that the snake can touch.
A lot of newb try to get the surface of the substrate to the temp they want and do not recognize that a snakr can and will burrow. It will be a lot hotter down below. I use paper towels in my racks.
Again just make sure the area they can touch or lay on is not over the temp you are wanting. There will always be a variant depending on heat loss.

[artgecko]

OK... I will try the UTH on the table and put everything in the tub as it will be when the tub is fully setup and see what happens... I am concerned that the added weight in the tub will make it bow downwards touching the UTH and possibly overheating the snake if it is turned up higher. I will try this first and see if it works, if not, I will attach the UTH to the tub and set it lower.

Thanks for your help!

[Slim]

Part of your issue is with the Ultratherm. I have used them in the past, and like them very much, but they do not heat the same way Flex-Watt does. When using Ultratherms I always had to raise the set point on the mat higher than I would on Flex-Watt to achieve the same measured temp on the inside of the tub floor. Don't know if it's because Ultratherms are made to EU standards, or if they are just designed to put out a lower heat value.

I will say that from a quality standpoint, they are top notch pieces of gear.

[artgecko]

Slim- Thanks for your input. I got the ultratherm from a durability and safety standpoint... I've heard that they hold up better than flexwatt and don't get as hot if the thermostat malfunctions... So would not be at risk of melting the tub.

I've got everything setup and I think I should be ok. My hotspot is reading 89 inside the tub now, although I need to verify that with my temp gun as well.

Thank you again for your help and advice!

[Slim]

Hard to beat the quality of the Ultratherm, that's for sure.