Ambient Temperature:   As stated above, ambient temperature refers to the general average air temperature throughout the turtle’s entire enclosure. The proper ambient temperature provides an adequate level of warmth for the operation of the turtle’s normal metabolic processes. Overall, the ambient temperature of the aquarium is one of your chief concerns in keeping your turtles healthy and growing. A good average ambient temp for Aquatic Turtles (and Box Turtles also) is between 78-82 degrees. Having an accurate thermometer placed midway through the aquariums dry area (away from the basking site) should give a good ambient reading.  The easiest way to maintain a consistent ambient temperature in the turtle’s aquarium is to place the aquarium in a thermostatically controlled area of your home. As long as the area outside the aquarium is maintained at 78-82 degrees, the inside of the aquarium will reflect the same temperature. If no specific part of your home is thermostatically controlled, then an area that has the most consistent room temperature should be chosen. This area is usually a place away from areas of extreme temperature fluctuations such as large open areas or spots directly next to windows and doors.

It will take a few days of reading the thermometer to know what the average ambient temperature is at the aquariums location you have chosen, and if you will need to add extra heating inside the tank to increase the ambient temps. It’s common that most homes are not maintained at 78-82 degrees, so usually some form of supplemental aquarium heating is needed. Fortunately, basking spot lamps will help to increase the ambient temperature, as they will not only provide directional heat for “sunbathing” but also add residual heat into the surrounding enclosure, effectively raising the ambient temps while they are in use. So, during the daytime, in a home with a more common average ambient temp of 72 degrees, with a working basking lamp contributing another 6-8 degrees of general heat, proper ambient temps within the enclosure should be possible without too much work.

But what about nighttime when basking lights are turned off and house temps tend to cool? How do you maintain ambient temps then? This is where two factors come into play, the first is the water within the aquarium. Water is a great mediator of temperature change; as the ambient temp drops in the absence of basking heat, the water will help transfer its own warmth into the air space, helping the air to keep warm. Secondly, if home temperatures turn cold at night, a ceramic heat emitter can take the place of the basking lamp during evening periods by producing heat but no light.

It takes a little while to get the ambient temperature stable, as many factors affect the outcome. If your house temps tend to be somewhat consistent, your job will be fairly easy, however if your house temps change drastically from day to night, or from season to season, it will take a bit more monitoring on your part to assure that the proper ambient temperature within the turtle’s enclosure is maintained.

Warming the Water:  As aquatic turtles spend much of their time in the water, the actual water temperature is an obvious concern. When dealing with turtle setups that have an equal air space to water space ratio, the water temp should naturally reflect the same temperature as the ambient air temp (an aquarium thermometer placed in the water should verify this). If this be the case, then separate heating of the water is normally not necessary and you’re in good shape.  If, however the water space of the aquarium is much larger than the controlled air space (such as an aquarium full, or almost full of water), it is likely that you will need some method of warming the actual water space. This is where a good quality, properly sized aquarium heater comes into play. These heating units, used most commonly for tropical fish, work well in most circumstances with aquatic turtles. Follow manufacturer’s instructions for setting the temperature at 72-78 degrees and place the heater in the aquarium in an area with good water flow. Secure the heater to the side glass where larger turtles are less likely to knock the heater around. After a short warm up time, the thermostatically controlled heater should maintain the designated water temperature.

Basking/Heat lamps:  Basking lamps are referred to as “directional” heating, meaning of course that they cast their heat in one specified path. Although the heat from these lamps eventually dissipates into the enclosure adding to the ambient temperature, their main purpose is to provide concentrated heat to a specific spot where the turtles can dry off and receive extra warmth similar to sunbathing. These types of heating units come in various forms; some that produce light at the same time (common clear/red basking spot lamps) and others that produce the same heat yet produce no light (ceramic heat emitters). Each have their own purpose and are staples in maintaining proper heating within the turtle’s environment. Basking lamps are also “timed duration” heating, meaning that they are only active for specific time periods throughout the day. Generally, most aquatic turtles should have a minimum of 6-8 hours of basking time each day.  The spacing from the actual basking platform and the heat lamp will be determined by the wattage of the heat lamp and the material of the basking platform. The higher the wattage of the bulb the more heat produced, the closer the bulb is to the basking platform, the hotter the basking platform is likely to be. The material and color of the basking platform can also play a part in either retaining or reflecting heat. The turtles themselves will actually tell you when you have the proper heat at the basking area.  If the turtles climb onto the basking area and slide back into the water after a very short time, the basking area is likely too hot. It’s time to move the heat lamp farther away. If the turtles climb onto the basking area and remain for hours and do not dry off completely, the basking area is likely too cool. It’s time to move the heat lamp closer to the basking area. The best situation for a single basking session is when the turtles climb onto the basking area, bask for 30-45 minutes, completely dry off, and then dive back into the water to cool off (normally this places the basking spot approximately 8-10 degrees over ambient temp or in the 85-90 degree range). It takes a little while to get the basking temperature right, but you’ll know by the turtle’s behavior when your there.

Review:  So, this then is the general review of all the avenues of heating the turtle’s enclosure you are likely to deal with. Each having its own role, and each working with the other to provide the appropriate ambient temperature of 78-82 degrees, basking temperature (as described above at approximately 85-90 degrees), and water temperature of 72-78 degrees.  It is also important to note that slight variations from these ideal heat temperatures can and will happen within your turtle’s enclosure; drastic seasonal changes, sudden local weather situations, and even power outages can all challenge us in maintaining the proper heating conditions within our turtle’s enclosure. Fortunately, temporary cooling due to circumstances unforeseen usually have no serious long term consequences as long as the situation is corrected promptly and proper temperatures are resumed.

On average, it may take a few days to a week to really dial in the proper temperatures for your turtle’s enclosure. Be patient and watch your thermometers, and your turtles – they’ll let you know when you’ve got it right!