What is the most efficient way to heat a large terrarium (for hermit crabs)?
I recently got a very good deal on a watertight 90 gallon aquarium – just $40 since they thought it was 55 gallons – and I need to plan an efficient terrarium for a colony of hermit crabs.
The tank is 2ft tall and in some places the sand may be up to 8 inches deep. My first inclination is that heat lamps will not be a very effective nor very efficient approach to maintaining 72-80 degrees.
I currently have a 29 gallon tank with a red incandescent night light and an under-tank heater which keeps the sand warm. At that depth it doesn’t have a huge effect on the air temperature and I don’t feel that it’s particularly safe, especially with no thermostat regulation.
Another option is to keep the water heated. Will one large fresh water and one salt water pool heated to 78 degrees help to maintain a good air temperature? Also, if the pools were adjacent, would I be best to divide them with glass, acrylic, or something else (ideally for the purpose of only requiring one heater and relying on some heat transfer).
I am primarily concerned with energy usage and effectiveness. The tank has a divided acrylic lid which allows airflow while keeping the humidity up as well.
Thank you, this will help to decide whether I should keep it or reframe it (the frame has been melted in a few places) and sell it for a $60 profit in the hopes of finding a smaller alternative.
Also, as a clarification, the hermit crabs will be kept either in the living room or in an extra bedroom in my apartment which will be evenly heated to around 70 F, so intense heating should not be necessary. The temperature in the current 29 gallon ranges from 70 to 80.
For my 100 gallon I use 3 heat lamps I bought at the hard wear store. they’re suspended about 10-12 inches away from the lid. I use home made plexi glass lids and so far no issues with heat or humidity. the lights are on a timer during warmer months and the lid keeps most of the heat it not letting it drop below what’s safe.
I’ve never heated the water dishes The heat lights keep the salt water pool and fresh water dishes a comfortable level.
Here’s a photo of my set up. The stand lid and light set up is home made. The tank cost us $40 and all together the supplies were under $300 ( that included some of the tank accessories sand etc)
http://img.photobucket.com/albums/v176/Mtoast/100gallon.jpg
Edit: I don’t know if you can see in the photo. but I have a dial that lets me turn up or turn down the lighting. So on days where the tank needs to be warmer I can turn the lights up on days where I need it cooler I can turn them down or off all the way. My Fiance installed it for me if you have a basic understanding of lighting and electronics it isn’t hard. You can even look up instructions online.
use a few mini hermit crab beach bonfires
It is not necessary for the substrate to all be warm, and the water will take on the air temperature, so you don’t need to worry about how warm it is.
I would NOT put the ocean salt water over a heat source, or under one for that matter, as evaporation can cause salt crystals to form, and these could get into a crab’s shell and irritate or injure it’s extremely soft abdomen.
If you use an under tank heater to heat part of the substrate (leave part unheated, so the crabs can choose the temperature they’d like), I highly recommend using a thermostat to control the temperature so the substrate temp never rises above about 81*F. Any hotter, and a crab could burrow down and obtain heat damage.
I have a 55 gallon. If I had a 100gal, I would still only use a heat mat for a 55gallon, and use overhead lighting. I have a reptile hood on mine with a day glo and night glo lamp.
I keep the tank covered with about a 1/2″ gap for air flow, and that helps keep the humidity stable in winter months when I use the heat lamps most of the time.
My fresh water dish is in a “rock garden” over the UTH, to help add to humidity. It has an airstone in it as a makeshift “bubbler pool” which also raises the humidity as well as keeping the fresh water fresher longer.
I also use a moss pit, spraying down the moss daily to keep it moist to also add humidity to the air.
For more info and for a great forum where you can have more questions answered, join forums. There are many very experienced crabbers there who have had their crabs for 10+ years. They also have info and advice from Carol at Crabworks, who’s crabs are now 33 years old.
Ugh it didn’t post the website in my reply. Hopefully it will be at the bottom when it’s approved, but in case it’s not, visit the Crab Street Journal website.