# Enclosure Experiments



## Balboa (Dec 19, 2010)

DISCLAIMER: 

This is purely an experimental exercise on my part, to investigate some theories of my own regarding thermo-dynamics and its application to tortoise keeping. I've decided to post a thread on it for the benefit of the curious. This is NOT intended as a guide or informational for those getting started in tortoise keeping.

---------------------------------------

I've had a few ideas I've wanted to play with bouncing around in my noggin, and decided to do some experiments. As I started these experiments I came to realize that I "skipped-over" some of what we might call "stages" in tortoise keeping. I stood on the shoulders of giants, learned from what they had to say, and built a large, dedicated tortoise enclosure from the start. This kept me from actually experiencing first-hand a few lessons. Now I'm going to hopefully learn some of those lessons as I struggle to investigate some theories.

In other words, I realize what I'm doing here is nothing new to most of you, but I'm hopeful there will be more than meets the eye.

------------------------------------------------------

For my first experiments I've set up two nearly identical enclosures side by side. These are 16 Gallon rubbermaid tubs, which are actually much too small to house tortoises, but hopefully large enough to simulate an actual enclosure.







They have about 2 inches of substrate, composed of half each Cypress Mulch (Zoo Med Brand Forest Floor) and Fir Mulch (Zoo Med Repti-Bark). (This is the used substrate out of the 40 Breeder Adrienne was staying in). I added 6 Cups water to each enclosure and stirred the substrate. This was enough to thorougly wet it, but leave little to any standing water. I then tamped it down flat.






Both tanks also have a little "drinking bowl" of water.
The left tank is obviously largely covered. It has a 50 watt halogen spotlight to create the basking spot and heat the enclosure.






The right tank is open topped. It has a 75 watt halogen spot.






The initial goal at this point is to stabilize both at comparable temperature parameters of 100 Basking and 80 mid enclosure and then check the resulting humidity in all locations after ongoing operation over a few days.

I'm already being surprised though. I can easily hit 110 basking with these setups, (too hot really) but the rest of the enclosure will barely rise above ambient room temperature of 67 or so (too cold). These plastic tubs are very different so far from what I experienced with glass tanks. I hope over time to see better temps, but so far I'm concerned about this style of enclosure (and that had NOT been the point of this experiment).

What I am seeing that I expected, is very low humidity measured at tort level on the basking spots of around 40% at present. With such low ambient temps this is no mystery, but I had honestly expected the covered enclosure to fair better than the open, and so far there is little difference, the open may be even fairing slightly better.

At this point its looking like I will need to up wattage in both enclosures and see how well things improve.


----------



## Becki (Dec 19, 2010)

Are you measuring with a temp gun? Just curious....


----------



## terryo (Dec 19, 2010)

What kind of tortoise whould this enclosure be for?
Throw in a bunch of plants, cover most of the top and you won't be able to see in there, it'll be so humid.
When I first got my tort, I started out with a tort table...not enough humidity, and couldn't maintain high temperatures....then a tub....same thing. Finally I used the same concept that I used for my boxies....loads of humidity. But the substrate was too wet and he started to get shell rot (fungus). Then I changed that and just buried the plants in their little pot. When I watered the plants, the water seeped out, but the surface of the substrate stayed dry. No more fungus. I keep most of the top covered. The humidity stays high, and so does the temperatures. I finally got it right. 
I guess that's how we learn...through trial and error.


----------



## Balboa (Dec 19, 2010)

Becki, Yep I'm measuring with both a temp gun and standard thermometers. The temp gun is of course for surface temps and the thermometers more for "air" temps.

Terry, no tortoise in particular, just a "generic" tortoise if you will at this point. Probably geared more towards grasslands as a middle of the road.

In essence its shared experiences like yours and others coupled with my own experience at keeping other types of critters that led me to largely bypass these types of setups for keeping the redfoots. I still see many tortoises kept this way. Open tops especially are still promoted by some, and is the standard in most of the common literature as this was the prevalent method for many years. 

I guess you could say, I already know this doesn't work, I'm looking into exactly why.


----------



## Turtulas-Len (Dec 19, 2010)

Try covering the one with glass, plastic, alum foil, something non porous, the wood could be absorbing the moisture as the heat dries it. Len


----------



## Tom (Dec 19, 2010)

Great work Balboa. I'll be watching this one for results and conclusions. I haven't set up a tort in a conventional "house" type situation for a while now. They've all been in my heated, humidified reptile room. This thread is reminding me how much difficulty I've always had trying to heat and humidify my reptile cages over the years. Its also reinforcing my newer notions about using giant, closed, "incubation" chambers instead of regular open topped enclosures.

I've also been concerned about the desiccating effects of these overhead heat lamps we all use. I'm thinking of taking a page from the redfoot keepers book. I want to try to keep a baby sulcata in a simple closed, heated "chamber". I've heard many times that they need to be able to reach 85 to digest their food. I'm considering a heated, humid chamber that goes from 90-95 during the day and drops to 80 at night, with NO basking spot. My babies always seem happy over the summer when their humid room get into the 90's.


----------



## Madkins007 (Dec 20, 2010)

Great experiment! I am wondering if the different heights of the bulbs would make it harder to compare results?

I would GUESS that the low overall temps in the rest of the tub is the cooling effect of the evaporation of the water under the bulb. Your enclosed tub is only partly enclosed and I would bet you are getting a heck of a chimney effect out of it. It might be interesting to measure the temp and humidity of the air outflow. I know when I mist my Tortarium that I can watch the mist flow upwards through the hole the MVB hangs down through. 

I would also like to know your ambient temp and humidity in the room- you said 67F for the temp- is that the room temp overall? I would also love to know the temps in the substrates in different locations. Got a probe thermometer?

If I may, I would suggest the following experiments:
1. Open-topped control habitat compared to a completely covered tub.
2. Open topped to 75% covered, to 50% covered, to 25% covered.
3. Is it better to have a central uncovered area, or openings on either side? (I'm thinking chimney effect and air flow with this one.)
4. Open-topped control to open-topped with a heating pad underneath
5. Maybe even an experiment for overall temps- 100% above compared to 75% above/25% below, 50/50, and 25/75 as far as evenness and stability of the heating- and if possible, cost effectiveness.


----------



## Balboa (Dec 20, 2010)

Thanks for the input guys, and yep, your thinking is right along the same lines as mine.

Len, that's a good point, and I failed to mention that the bottom of that piece of plywood is lined with linoleum. 

Tom, as you said, (and already know from previous posts) dessication is the primary motivation to this. I've read enough "evidence" to really concern me, and I fear that MANY torts are at high risk for this. There's a good chance that the majority of torts in captivity have suffered internal damage from it. I believe it was Danny that first really stuck that idea in my head good. If I recall correctly he's of the mindset that internal damage from dehydration is the cause of pyramiding.

Mark, I think you're on to something with the chimney effect and evaporation, and the same thing crossed my mind last night. I wish I had a thermal camera. I hadn't planned on quite as many permutations as you layed out, but close. 

I'll be fiddling with these some more this afternoon and see if I can get some better data.

-oops one more thing. I like that idea for the baby sullies Tom. That reminded me of my 93 degree thread that never went anywhere. I have still continued to find that my redfoots will be around 93 degrees if active. I need to start checking their resting temps now for those day time naps.


----------



## Edna (Dec 20, 2010)

Len said:


> Try covering the one with glass, plastic, alum foil, something non porous, the wood could be absorbing the moisture as the heat dries it. Len



This is just what I was thinking! On my big enclosure for my baby leos, I have the top covered with acrylic. Evaporation = cooling, so if you reduce evaporation, your ambient temps will be better. I also added the heat cable in the substrate, and the little girls are very grateful. I don't worry about the humidity right at the basking spot because they spend relatively little time there.


----------



## Balboa (Dec 20, 2010)

DAY 1 RESULTS
-------------------

A Word about Humidity:
Relative humidity (what we normally measure in our homes and for animal keeping) is temperature dependant. Its RELATIVE to the amount of water vapor a volume of air can hold at a given temperature without that water precipitating back out. The hotter the air, the more vapor it can hold, and its on an exponential curve. You can read more here and see the graph here .

This is an important concept to understand for tort keeping, as you warm air it becomes drier unless you add more water vapor.

-------------------------------------------

My results are largely invalid at this point unfortunately. My current home humidity level is 70% !!!!!! This would actually be too high, and we should be airing out the house more. That raises the heating bill though, so in a rock and a hard place.

This means that my results here are MUCH better than the average temperate household should see. Knowing that, these results are not encouraging.

Also remember, that my instruments are not lab grade, just the same kind of cheap junk available to the "normal" keeper. As such I have tried to confirm measurements between different devices.

----------------------------------------------

OPEN TOP:

I settled on a 75 watt halogen spot, combined with a 75 watt incandescant flood to reach goal Temperatures as pictured here.






This was the only way to significantly raise ambient temperatures, "spillover" from the basking spot just doesn't cut it. I've "seen" pictures and read claims to the opposite, but in my situation it just doesn't happen.

The Cypress Mulch is doing what it should, its staying wet to the touch, wicking up the moisture as it evaporates. This reminds me that I will need to repeat these experiments with different substrates.

Room Temperature was 70 F and Humidity 70%

Basking Tile: 123 F Surface, 103 F "In Substrate", 90 F Air, 50% Humidity
Tank Midpoint: 83 F Surface, 84 F "In Substrate", 80 F Air, 65% Humidity

"Mostly" Closed Top:

Yes, the 50 Watt Spot sticks down much farther into the enclosure than could be allowed on a normal enclosure. I was able to hit target temps like this. 






Again, Room Temps were 70 F and Humidity 70%

Basking Tile: 125 F Surface, 90 F Air, 86 F in substrate, 50% Humidity

Tank Midpoint: 83 F Surface, 80 F Air, 79 F in substrate, 70% Humidity

-----------------------------------------------------------------

Surprising to me to say the least.

Open top worked far better than I expected, Closed top far worse, and in both cases the basking spots were not nearly as bad as I had anticipated. I would really rather see a much higher than 50 % reading for safety margin however, that is still a "drying" humidity level. Closing things up only slightly boosted humidity, but it did raise thermal efficiency GREATLY.

Obviously there are some MAJOR caveats here:
"Baseline" humidity in the room was higher than it should be, that likely means these humidity readings could be as much as 50% higher than they would be in a "normal" home.

Even in my overly humid home as it now stands, these setups would only be suitable for grassland species, there was no way to make these redfoot capable, the substrate is already drenched. A grassland kept on dry substrate in these conditions would dehydrate. (Well I guess that's another test that needs conducting, need some dry substrate now)

Considering the amount of power needed to heat even this small open top enclosure to goal levels implies staggering wattage may be needed to make a full size enclosure work. Economies of scale may not play out like I anticipate, but I will estimate then that a 2x4 foot enclosure, being more than 4 times the size of this test one, would require 600 watts of heating (at least by overhead light, of course CHE useage needs to be looked at as well). I don't believe I've ever seen 600 Watts hanging over any enclosure.

I am now going to slide the water bowls to the cool side for a bit to see how much they were contributing.

Next up I will try some belly heat.


----------



## Tom (Dec 20, 2010)

Keep going man. You are on a roll.

Very good stuff.


----------



## PeanutbuttER (Dec 21, 2010)

I'm excited to see the belly heat results. Good job, keep up the great work.


----------



## Madkins007 (Dec 21, 2010)

A thought... what if you positioned a wet sponge on a piece of foil right in the middle and tracked its weight? That should simulate the actual dehydration in the tortoises living in there. The faster the sponge dries out, the more dissecating the habitat would be. I am wondering if there would be a big difference with THAT as the key question? 

My guess would be that the airflow in the open habitat would be more drying than the partially closed version, but that is just a guess. Have you seen much difference in how the water in the substrate is drying out?


----------



## Balboa (Dec 24, 2010)

Been too long since I worked on this, got sidetracked with other things. Hopefully after christmas I can get rolling again.

I like that sponge idea Mark. I had thought about using a couple of those christmas oranges we have laying around here, but the sponge sounds like a quicker results option.

I ran into a bit of a roadblock with the belly heat. Belly heat really did nothing in the open top, and only helped a little in the closed top, so not much to report there, maybe a 5% improvement.

I still think belly heat is useful in clamminess prevention. As you all may recall from the first set of data, the closed top actually had cooler in-substrate temps than the open top.

That being said I think it will be time to try out some different substrates after christmas. Naturally, dirt is at the top of the list. I suspect results may differ greatly considering the greater density of a dirt substrate.

By observation, yes the open top dries out quicker than the closed top. I'm beginning to think chimney effects are far stronger than expected and hindering even the mostly closed top. Obviously a totally sealed top would yield the best humididty, but that's not really practical.


----------



## PeanutbuttER (Dec 24, 2010)

Personally, I have a hunch that "belly heat" is much less about heating the enclosure and much more about "clamminess" and its health problems. My hunch is that belly heat will reduce occurrences of shell rot. 

Of course it also helps with humidity, which is another big plus.

Also, what kind of belly heat did you use?


----------



## Tom (Dec 24, 2010)

Sent to me by Tyler:










It is doable. I'm looking at something like this, but with belly heat. Giant incubation chamber.


----------



## Balboa (Dec 27, 2010)

I'm going to have to try 99.9% coverage like that, obviously mostly covered doesn't cut it, likely due to chimney effect. In the future I'll be advising those that try a partial cover not to waste their time 

I botched an experiment today, but the results were still somewhat interesting.

I filled those little tupperwares you see in the pics with 1/4 cup of water and placed them on the basking tiles with the plan of monitoring which one dried out first and how long it took. I then promptly forgot about it.

7 hours later both were bone dry. 

1/4 cup of water evaporated off in less than seven hours even in the mostly covered enclosure with 75% or so humidity. That speaks volumes to me about torts that hang out under the heat lamp too long.

Of course, open water may evaporate easier than a "semi-permeable membrane", hence the need for Mark's sponge idea, or a carrot or orange or the sort,


----------

