Habitat - Outdoor :: RES hibernating in pond

[MamaLou]

My Res's are in their pond now and quite happy. About 1000 gallons, bi level. Temp is at 55-60 during the day lately, its getting chilly here NC. Small res is spending tons of her time under the leaves that have fallen in, and Mamalou is out and about still basking and eating. I just want to know what anyone knows about hibernating and temperatures and time of hibernation and such. Do I need a pond heater? If so what kind? I am sure it wont freeze over, doesnt get that cold here. Any help would be appreciated.
~Mamalou

[CountryGirl68]

Although it is okay for a captive turtle to hibernate, it is not necessarily a good idea to do. For your turtle to be able to hibernate in your pond, the pond must be at least 3 feet deep with a deep enough bottom layer of mud where the turtle can burrow into to keep warm. Also, you should have a surface heater because in the event the top of the pond freezes, there is no way for oxygen to get into the water. It is also recommended you have some form of water aeration system to help oxygenate the water.

Finally, if your smaller res is less than 4", it isn't recommended you leave it in the pond during the winter, since they are more suseptible to infections that adult res.

[MamaLou]

Well the baby is about 5 inches now, and Mamalou is close to 9 inches. The pond is 3 ft deep, and the deep part is full of debris sand and leaves that have fallen in, she tends to bury herself in it. The pond also has a spitter, an excellent filtration system, and gets fresh water every other day after evaporation. No chances of freezing, but if there were, what type of pond heater should I get? I am out there everyday visiting and checking up on things.
Thanks.