Heating Turtle Tanks

In the wild, depending on the latitude, the temperatures to which a 
turtle is exposed vary widely. 
While there are recommendations for many species, none of these rules are
hard and fast. 

For water turtles, a good temperature is around 80F. At this temperature
the turtles' immune system works well, they eat well, and they are comfortable.

When the temperature is around 50F/10C, turtles start thinking about hibernation.
If the temperature is warmer during the day, but drops below 50F/10C at night, 
this is true, too. They will stop eating, but their metabolism will not slow down
very much. A turtle that stays in this limbo state for too long, will get weak, sick,
and eventually starve.

If you are more ambitious, find out from a field guide, where your kind of 
turtle lives and what temperatures it prefers; then set up its environment
accordingly. Be generous with warmth. Many turtles get sick and die because they
were too cold for too long.

The following gadgets will help you heat your turtle enclosure:

* Incandescent light
  This is the ideal way of providing a basking spot. The temperature of the basking
  spot should be between 85F and 95F, depending on the kind of turtle.
  All turtles must have a basking area that is on land and dry.

* Fluorescent light/Full-spectrum light
  This provides little heat. Fluorescent light can illuminate an enclosure, and it
  can help plants grow in it (algae, too). If you use a full-spectrum lamp designed
  for reptiles, you don't have to supplement with Vitamin D3, usually.

* Infrared light/Ceramic bulb
  These heat emitting bulbs are suitable for animals that need to be very warm at
  night, too. You can also use such a bulb for a basking spot. However, ceramic bulbs
  are expensive. They also last forever.

* Heat rock
  Is an alternative to a lamp to create a basking spot and heat the enclosure.
  The problem with most heat rocks is that they are too hot, and if the rock
  overheats, and the reptile sits on it and doesn't notice, you will have a 
  very dead and very dry animal in the best case. In the worst case, your animal
  will have severe burns that will require treatment. 
  I don't recommend heat rocks.

* Under tank heating pad
  These are a good solution. Ideally, they would be used with a thermostat, but few
  of use can afford a thermostat per pad. You can use a pad from the drugstore designed
  for people, or you can use a pad especially designed for tank heating. All pads 
  are recommended only for glass tanks. The reason being, of course, that if the pad gets
  too hot, would will char and plastic will melt. These pads have varying levels of
  heat, depending on brand and setup. 
      For a pad that does not need to be stuck to the tank, I use a cotton towel 
  between the pad and the tank to prevent burns.
      For a pad the does stick to the tank, I make sure the pad is covered with
  newspaper in such a way that the animal cannot sit directly on the pad.
      You can also heat a tank filled with water using such a pad. The advantage is,
  that the animal will not break the heater. However, this is not a very efficient way
  of heating a water tank.

* Submersible aquarium heater
  Used for water turtles. Since water turtles can break an aquarium heater, you should
  put it behind rocks, or inside a tube (make sure water circulates well through the tube,
  for example, by adding slits on the side). These heaters have a thermostat and will
  maintain an even temperature. Don't forget to turn it off when you change the water.

* Heat tape
  Good solution, especially for shelved tanks. Usually some assembly is required.
  Usually, the tape is stuck to the tank. Make sure the animals cannot directly
  sit on the tape. 

Use a thermometer in each tank, and check it regularly!
If you live in the South, and it gets hot, invest in a thermostat that will turn off
the heating pads when it gets too hot in the room or the tanks.
Breaking Aquarium Heaters
Reader tip from markw@voicecrystal.com:

    "One item I had for you was regarding submersible aquarium heaters.
   Even though we live in an area that averages 80-85 degress in the
   summer, it often gets up to 95-105 degrees... so they love it. In the
   winter they slow down a bit, and sometimes (if I find it's going to get
   very cold 40 down to frezing, I will pull out my two 300 watt aquarium
   heaters. These I do put in a protective screen, however, I do loose some
   heaters due to internal leaks and breakage. Should this happen the
   turtles would undoubtedly be electrocuted if it wasn't for the GFI
   protection device I place in between the wall outlet and the electrical
   cord that supplies power to the heaters. They can be purchased almost
   anywhere including Kmart. It is a foot long extention cord with a GFI
   (Ground Fault Interupt) breaker built into the cord. A GFI will
   disconnect power even with most minute current so that it will
   disconnect even if you put your fingers accross the terminals... so you
   won't get a shock.

Note: Putting the heater into a rock  cave or a plexiglass tube with slits
      will also protect it from turtles banging into it.