Help! Heating ideas for 15-gallon glass bottle habitat...

Andre0170 · Post by **Andre0170** » Wed Mar 29, 2017 9:31 pm

Howdy... considering creating a crabitat out of a very large 15-gallon glass demijohn bottle (see pic) where substrate would be filled to the units widest point, and separated by stones between sand on one side and coconut soil on the other. Current crabs are in similar setup but in a traditional 10-gallon rectangular tank (successful for three years now). The bottle neck would be cut off down to where about a 9 or 10-inch opening would be created. Trying to determine how to heat properly. Could affix a heat lamp to a screen that would be on top across the opening, but the lamp would likely be more centered due to the bottle shape, which would heat the entire enclosure rather than keep one side of the substrate warm (sand) and one side cooler. House is usually 68/72 in winter, similar in summer, pending warmer weather on some days. Consider a heater pad? Some creative heater placement under the bottle within a shallow raised platform that the bottle sits on? Something on one side of the bottle near the substrate? Just go with a top lamp? Bad idea...? Any thoughts? The crabitat would be pretty cool if I could make it work... thank you!!!

Pic can be seen here: http://i.ebayimg.com/00/s/MTYwMFgxMTc5/ ... 5o/$_1.JPG

Post by **aussieJJDude** » Wed Mar 29, 2017 11:27 pm

I personally would just stick with the conventional tanks. How wide is to bottle....? Also stones probably won't stop the crabs from mixing up the substrate and will mostly be a waste of mounting space imo. Heat lamp would work great... but the humidity... for some it's fine (Like me) others not so much.... you may need ways to increase humidity....
I personally would turn this into an amazing terrarium... but that's me.

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Andre0170 · Post by **Andre0170** » Thu Mar 30, 2017 5:49 am

Thanks for replying! The terarium idea has crossed my mind, but I don't want to let go of the crabitat use yet. The current rectangular tank setup has substrate separated by large, flat stones stacked on top of each other - at the surface they show as just flush with the surrounding substrate on either side. They are 2.5" wide or so and the substrate has never been mixed up since I started using them. The bottle is actually wider than the current tank so I'm thinking what I lose in length, I gain in width. Dimensions of the bottle are 18" wide at the base, 22" at the widest point. 25" high, but I'd have that cut down several inches to make an opening the same size as a top screen and wide enough to service the crabs. So it'll likely be around 19" tall. The substrate filled to the widest point will likely leave 10 or so inches from the top. That would actually give them a few inches more to dig down than they have now. I always hear them scraping the bottom of the tank currently when they burrow. No issues with humidity - the coconut substrate half of the tank I keep damp with a mister almost daily. I would do the same with the bottle. You think a top lamp would work for heat? My concern isn't that it wouldn't heat enough - we can control for that - it's that I read that hermits like one side of substrate warm and the other side cooler. So on a rectangular tank having the lamp on the "sand end" accomplished this. With a round enclosure, the heat would be more universally distributed. If that doesn't matter much, I may give this a try.

daws409 · Post by **daws409** » Thu Mar 30, 2017 6:31 am

I'm with Aussie on this one. A regular tank a better IMO. It may seem like a good idea, but what happens when the crabs grow? They'll need the extra room that a rectangular tank provides.

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Andre0170 · Post by **Andre0170** » Thu Mar 30, 2017 7:10 am

Thanks for jumping in... as far as space considerations for growth, the 15-gal bottle is pretty big and unless I''m mistaken, would be an improvement over the current tank. Surface area of the current tank provides 200 square inches at the substrate surface, and about 3" of substrate depth. The bottle would provide 315 to 380 square inches of surface area (depending on how high I were to fill) and 6 or 8" of substrate depth. It's really big. It's how best to heat it that's got me more concerned - particularly with crabs seeming to prefer warmer on one side of substrate than the other. Not easily accomplished with round bottle. Any thoughts?

YouTube · Post by **GotButterflies** » Thu Mar 30, 2017 10:01 am

Perhaps I'm having a hard time imagining it, but you lose "gallons" but cutting off the top, so your crabs really wouldn't gain much more space than they already have. I agree with aussieJJDude & Daws...I would stick with a regular tank, but that's me. I don't see how you could really keep a cool side and a warm side with this kind of bottle tank.

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silverblood72767 · Post by **silverblood72767** » Thu Mar 30, 2017 12:11 pm

Surface area and molting area are very important. So saying you would end up with the same space and a rectangle is better isn't true. Imagine if ten gallons of space were taken up by having one square inch with really high walls, a standard five gallon would actually be the better tank at that point because there is less usable space in the ten gallon. The bottle would have more usable space than the tank, it's just shaped different. She's also asking for help making this work, not to be shot down without any help. That being said, using more hideouts or little platforms for hides would keep the substrate underneath cooler even though the whole tank is under heat. You could cover the hides with moss to help with humidity and make it look really natural.

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Post by **aussieJJDude** » Thu Mar 30, 2017 3:18 pm

Ah ok. So pretty big bottle. Gallonage and size can vary from tank to tank... which was the reason I asked. As a liter and a cm man myself, I still sometimes need length x width x height to help me fill in the spaces.
In the short term it will work, but then again crabs can and will outgrow anything smaller than a 40g imo. That being said, if you want this setup long term and get the most use outta it, I would stick with the crabs you have now.... getting more will require an upgrade sooner or later, which will save you less time to enjoy this setup (aka. It can work).
Like the comment above decor in the tank will naturally contain zones and have microclimates inside the bottle. So a heat lamp can work, it's just finding the balance. You may find that you will need to buy multiple wattage lamps so you come into a balance... or you may be lucky from get go. I heated a 20g with a 100 to 150 watt lamp so you may want to look at 75 to 150 watt lamps.
(I personally would loose the stones, dovodong up the substrate area in smaller tanks in effect decreases the amount of burrowing substrate available... which can increase in problems.)
Plus rounded tanks weren't the problem, if anything it increases the walking room ( crabs can go round) but it's more the size that I was curious about.... rounded tanks can work just like the conventional rectangular tanks can.

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silverblood72767 · Post by **silverblood72767** » Thu Mar 30, 2017 7:51 pm

I'm the same way. Until i heard the dimensions I thought the bottle was too small. Using a dimmer would make it easier to control the temperature without buying lots of bulbs. If you go ahead and invest in a good one you'll have it from tank to tank in the long run, so it'll be a nice addition to your supplies for any tank.

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Post by **aussieJJDude** » Thu Mar 30, 2017 7:53 pm

True dimmers. Always forget about those. They work great

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Andre0170 · Post by **Andre0170** » Thu Mar 30, 2017 8:54 pm

Thanks everyone for the comments. I think I will indeed give this a try! I'll post a pic once I get it set up. Really appreciated!

soilentgringa · Post by **soilentgringa** » Fri Mar 31, 2017 2:04 am

This bottle is not and would not be a suitable habitat for hermit crabs, regardless of any modifications made.

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Hermiearth · Post by **Hermiearth** » Fri Mar 31, 2017 5:50 am

soilentgringa wrote:This bottle is not and would not be a suitable habitat for hermit crabs, regardless of any modifications made.

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Is there a specific reason you have? I know there is dispute but I am trying to figure it out.

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silverblood72767 · Post by **silverblood72767** » Sat Apr 01, 2017 2:08 am

Saying something as though it's important is kind of worthless unless you give reasons. There is no reason this bottle would not work as a habitat.

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Hermiearth · Post by **Hermiearth** » Sat Apr 01, 2017 2:47 am

Let's not cause a fight here. There are some questions that arise with the bottle, such as space heating and so forth, but I agree that we should try and figure it out and not shoot down someone's idea.

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HCA: Hermit Crab Association