Glass-top, Front-Opening Terrarium?

[daws409]

Would it be best for the UTH to cover the entire back or just one end to make a gradient?

Largest that fits along the back and ABOVE the sub

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[Hermias_mom]

Would it be best for the UTH to cover the entire back or just one end to make a gradient?

The UTHs come in set sizes, so most folks just get the largest one that will fit on the back and still be above the level of your substrate. A natural gradient occurs throughout the tank by doing this, if the crabs get hot, they'll bury in the substrate, if they're cold, they'll climb the decor to try and be closer to the UTH. But you can put the UTH on the end if you want to. Doing that decreases the size of UTH you can use (the tank end is smaller than the back), and so if the tank doesn't get hot enough after insulating, then you'll need to buy a larger UTH and mount it on the back.

Also bear in mind, minimum recommended temperature is 80F. A good upper limit is 85-86F. Some crabbers create a day/night cycle to mimic their native habitat with a temperature fluctuation of about ten degrees or so over 24 hrs, but I'd recommend doing some more research on this before trying it out. Might check out some of Wodesorel's posts, I think she talked about this at some point.

You can use a thermostat with your UTH if you want the tank to hold a set temperature all the time. I do this, and my temps fluctuate 79-81F throughout the day. I like the peace of mind, knowing that my crabs won't get too cold when I'm not around, or too hot. My thermostat is a Zilla, and works great, but there are definitely other brands that work just as well.

[Lephantome92]

Is there any reason i shouldn't put it on the top half, so i can have deeper sub? If i do put it on the top, should i grab an 11 or 6 inch one? Currently i have a high of around 83-84 during the day, then around 75-77 at night because it's only the moon bulb and a small uth

[Hermias_mom]

Is there any reason i shouldn't put it on the top half, so i can have deeper sub? If i do put it on the top, should i grab an 11 or 6 inch one? Currently i have a high of around 83-84 during the day, then around 75-77 at night because it's only the moon bulb and a small uth

You just don't want to put the UTH over the substrate (like where the substrate is directly opposite the UTH with the tank glass in between). SO if you have a 10 gallon tank, that gives about 10-11 inches of open glass on the back of the tank. Subtract 6" for substrate, and you're left with 5-6" height of open glass you can put the UTH on. So for my ten gallon I bought a 6" wide snake strip and angled the sand away from the tank wall a bit so that the substrate touching the wall was about 4.5 inches deep and didn't go up over the UTH. It was a temporary fix until the 29 gallon got set up, because the crabs move the sand around a fair bit, and it wouldn't stay at 4.5" deep right next to the back wall of the tank.

Now, if you're asking if you can put the UTH on the glass top of the tank, I don't see why not, as long as you don't bend the UTH, and there's not anything touching the glass immediately opposite the UTH that might get overheated. Also, I'd be concerned with heat input into any soft plastic parts of the glass lid. If it's regular aquarium glass, that should be okay I think.

Here's some pictures/info that might help explain. I'm not sure I fully understand your question, maybe these will help.

Care sheet that shows a typical crabitat, with good info on how to mount and size a UTH:
http://www.hermitcrabassociation.com/ph ... 51&t=92457

Daws' setup showing a UTH on back of her bottom tank in the 1st and 4th picture on the second post. She has a 6" wide snake strip (from what I can tell).
http://www.hermitcrabassociation.com/ph ... 8&t=114078

Picture 3 & 4 of my former 10 gallon tat - if you look, you can see the black heat strip covering the back of the tank - the silver bubble wrap stuff is the reflectix insulation - I had the 6"x23" one, and it stuck out from the back by like 3 inches. When I mounted it in basically the same place on my 29 gallon crabitat (including the reflectix insulation), it doesn't get the tank quite hot enough to suit me. I'll have to add more insulation or get either a second UTH or a bigger UTH.
http://www.hermitcrabassociation.com/ph ... 8&t=114062

Hope this helps.

[wodesorel]

The UTH can overlap substrate. I've always had my tanks set up that way. The recommendations I always knew were the entire back of the tank.

[Hermias_mom]

The UTH can overlap substrate. I've always had my tanks set up that way. The recommendations I always knew were the entire back of the tank.

Oh, okay. That's different. No problems with your substrate drying out, or forming hot pockets in the sand? (Do you have 5:1 playsand/coco-fiber substrate moistened to sandcastle consistency with marine saltwater? Do you have airstones in your water pools? Sorry, I don't recall your setup.)

I would think the same concerns would apply when putting the UTH on the back over a lot of substrate as would apply when mounting the UTH on the bottom of the tank, and I've heard that hotspots on the bottom (areas of overheated/superheated sand which form because sand is an insulator and there's a constant heat input from the UTH) can cause concern for molters. Of course, the crabs could just burrow on the other side of the tank from the UTH, when it's mounted on the side, if they need to, but they can't do this if the UTH is mounted on the bottom.

You've been at this a lot longer than I have. What's been your experience with hotspots and substrate drying out?

[daws409]

@Hermias_mom Yes! It's a six inch strip. It's a 6x47 UTH from reptile basics. This tank is 72" (6ft) long so I prob could have used the 6x47 and a 6x23 side by side. However, considering I have exotics that need UVB lighting and they do put off a little heat, I didn't need the extra UTH.

Here's more pics before anything was added to the tank. The blue tape is the minimum 10" substrate line... My substrate is 8 inches on one end and 16 on the topper side.

Edit to add: I insulated the UTH with a huge piece of cardboard.



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[Lephantome92]

Does anyone know of a uth ever melting the top rim of an aquarium? If not, then i have my setup mostly figured out!

Edit: Are only certain species of grape vine that are safe for a tat, or are most vines safe?

[wodesorel]

The only tank I have supplemental heating on is my 10 gallon. Straight sand moistened with saltwater since I'm allergic to cocofiber and needed mold control. 50 pounds of it. Pad is lightly insulated with aluminum foil and cardboard, never needed more than that even though the room hits very low 60s in winter. Tank stays between 80 and 87.

I do an 11x11 pad on the back of the tank which is 12x20. (If I could find a size that would cover more I'd have done that.) No overheating where the sand it, and since there is evaporation from around the heater it helps with humidity so I've never had to mess around to get a perfect 85%. I have to pour a glass of water in front of the heater every month or so to keep up with that evaporation but the sand stays a good consistency and I never need to mix. I don't find it to be any different then when I was using heat lamps, or any of my room heated tanks.

I like that it heats the sand as well, so they can get a gradient while molting. Especially in winter, the bottom half of the sand can be as cold as the room and often that is just too cold. This gives them the option of seeking out the level of warmth they want without having to molt shallow.

Hot spots aren't as much of an issue when it's on the back of the tank, as the pad can release excess heat out the side not against the tank. When it's trapped underneath then both sides are boxed in and that's when it gets too hot and causes problems. I even have a substrate filled tank for one of my reptiles where it's basically set up like a hermit tank, and have a heater on the bottom for a warm area. Since it's on a wire rack it doesn't overheat. (Would never recommend this for hermits, the pad does nothing to warm the air.)

[Lephantome92]

Would hotspots be a major concern in a straight cocoa fiber tank?

[wodesorel]

Less than sand as cocofiber is lighter and doesn't compress as severely so the heat penetrates farther.

All cocofiber tanks are at a higher risk of oversaturation and flooding, and also of drying out a day having caves collapse, so keep that in mind. The top dries out while the bottom stays soaked. I've done it before, but it's a lot more of a headache that mostly sand substrates. The benefit is a lighter tank and less weight to have to carry home, but the downside is it's more challenging to keep stable.

[Lephantome92]

So the PP i thought may be molting came up and didn't have black tips, so he was either being shy or sneaky. That just means one less crab to worry about before the transition!

[Lephantome92]

Well, the tanks are now settled. Pictures will come soon!

[Lephantome92]

Sorry for the extended delay with pictures. I just never sat down at my computer to do it. Anyways, here we go

The whole crabitat:


Better view of the bottom:


The two levels:


The maple they have yet to climb:


Pots for hiding/climbing (Lief likes to climb the big one):


Lief (left) and Dwebble (right) climbing on the 1/4" rim:


Dwebble trying to climb over Lief:


I scared them :

[daws409]

Looks good! I see you decided to put the 20 on the bottom and the terrarium flipped upside down on the top... Did you ever figure out the UTH??

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