False bottom used to cool terrarium?

[Lamb]

Hello all,

In preparation for summer, I'm looking into methods to cool a 10 gallon marbled salamander (Ambystoma opacum) tank that I will build. I've read the Caudata.org cooling article, as well as done a search for cooling ideas. The majority of those for terrestrial tanks appear to use cool air, which I'd like to avoid in order to prevent dessication or force my sals to remain below ground. I was wondering if anyone has ever rigged a false bottom to keep a tank cool? Thus far, my general idea has been to run tubes into the false bottom that are attached to pumps, and have the pumps in a small ice chest with a couple of ice packs. Theoretically, there would be a constant circle of cool water into the false bottom, and warmer water out. Has anyone tried something like this? Even without a pump-cooling system, do false bottoms tend to keep terrarium temps down? Suggestions or other ideas are welcome.

 

[FrogEyes]

It should work, but not as well as possible. Heat rises, so it will be more effective if incoming cold fluids move down from the top, rather than across the bottom. If cool water enters from the top, it could also create a cold spray in the warm air, which will improve the cooling even more.

 

[thinkinfeller]

It should work, but not as well as possible. Heat rises, so it will be more effective if incoming cold fluids move down from the top, rather than across the bottom. If cool water enters from the top, it could also create a cold spray in the warm air, which will improve the cooling even more.

I'm not sure that temperature stratification would be an issue in a 10 gallon tank, especially considering that Ambystomids are not arboreal.

One idea I've toyed with, is cutting a loop into a 1/2" copper water line feeding my kitchen tap, and bypassing it through a 1/2" copper coil in the bottom of my enclosure. In doing this, cold water would be moved through the coil in the tank everytime my kitchen faucet is opened, eliminating the need for ice machines, or anything else that requires maintenance etc.

 

[Jennewt]

I'm not sure that temperature stratification would be an issue in a 10 gallon tank, especially considering that Ambystomids are not arboreal.

One idea I've toyed with, is cutting a loop into a 1/2" copper water line feeding my kitchen tap, and bypassing it through a 1/2" copper coil in the bottom of my enclosure. In doing this, cold water would be moved through the coil in the tank everytime my kitchen faucet is opened, eliminating the need for ice machines, or anything else that requires maintenance etc.

Neat idea, but what is the temperature of your incoming tap water in summer? It might not be cool enough to make a difference.

 

[thinkinfeller]

Neat idea, but what is the temperature of your incoming tap water in summer? It might not be cool enough to make a difference.

Cold water typically comes out of the tap between 42 - 48 degrees F year round. City water lines leading to and entering houses are located at the footings of the house, usually 5 to 8' below grade where temperature is fairly consistent.

rolls of 1/2" flexible copper can be purchased with a special coating to prevent rusting, rotting, and leeching with the metal.

This is something I wanted to put together last Summer for a 40 gallon tank housing 1.0 Platysternon megacephalum (Chinese bighead turtle) and a 10 gallon tank holding 0.1 Ambystoma opacum.... didn't get around to it, maybe this year.

Dan

 

[FrogEyes]

I'm not sure that temperature stratification would be an issue in a 10 gallon tank, especially considering that Ambystomids are not arboreal.

Nor, for the most part, are they aquatic. Let me re-describe the problem I see: the cold water is at the very bottom of the tank. The warm air is above it. Cold water running UNDER warm air and substrate will absorb very little heat.

Cold water dropping THROUGH the air will absorb more heat, and should also remove more of that heat effectively by evaporation, since more of that water will already be airborne.

This is a form of countercurrent system, like a "heat exchanger" or a kidney. Such systems work best by having the low concentration and high concentration fluids move parallel and opposite to one another. You could also achieve this with the copper piping by running the pipe against one or more sides of the tank, from top to bottom. I've often toyed with adding a massive computer heat sink [the big ones designed for custom gaming machines], and you could probably do well with one of these either alone or in combination with cold water flow.

What I'm suggesting is just a more effective way of exchanging heat, which is apparently your goal, and it doesn't have to have a huge impact on the habitat provided.

 

[Greatwtehunter]

Easiest and cheapest method is to just increase their substrate to 5 or 6 inches and stick the container on the floor (preferably bare wood or concrete) in a corner far from the nearest window.The salamanders will just dig deep to escape the warmest days.

My opacum, as well as all my other Ambystomids, are routinely exposed to ambient air temps ranging from 80-85f. I've stuck temperature probes into the substrate to monitor temps at the level they dig down to and it has never risen above 74f, even on the long stretches of a heat wave.

 

[grius]

Interesting discussions and ideas

Im kind a stuck to methods using a freezer, and maybe a construction like this could be a good option?

If you use a wood tank and make the bottom waterproof it could work. And a tap for misting water and all that. But the bottom will probably get Very chilled! so a timer or thermostat conected to the fan inside would be neccessary. Same way as too cool down from above. Coold air blowing in with help from a fan.

 

[Kaysie]

I would think that running a tube through the substrate would be more effective. Heat transfer is more efficient between two solids (tubing and soil) than it is between a gas and a solid.

 

[Lamb]

My other idea is to just have the tank in a larger, insulated, short tupperware containing water and ice packs so that the water is at or just below the level of the soil. Of course, I would have to replace the packs and water daily.

A friend suggested building an insulated wall arround the back and sides of the tank and then cutting a hole to fit a small fan. He thinks that the fan continuously moving air out of that space would keep the tank cool. This seems similar to other air-conditioning driven designs, but it doesn't blow air into the enclosure (which I'd like to avoid doing because I'd like to encourage surface activity).