Posted: Wed Jan 21, 2009 2:38 am
It depends.
The recommended distance for the UVB bulb should be specified on the bulb's packaging. Different types and brands have different strengths. The correct distance ranges from around 10" to around 16", which is why it's important to know the manufacturer's recommendation.
The optimum distance for the heat bulb is the distance at which the basking platform is heated to the temperature your turtle prefers, usually around 90 degrees or a little more. If the heat bulb is strong, then it will need to be further from the platform. If it's not strong, it will have to be closer to generate enough heat. A myriad of other things also make a difference - the ambient room air temp, whether there is a cover over the tank or not, whether there is a draft in the room, what type of fixture the bulb is in, for instance. The only way to know what's right is to check the temp with a thermometer, and then observe your turtle's behavior. Some turtles like it hotter than others.
SpotsMama