Posted: Fri Dec 14, 2007 5:00 am
The most common reason for turtles not basking is that the heat differential between the basking platform and the water isn't great enough. Turtles are natural born heat seekers. You need to keep the water at around 78 degrees (if they are small, or 75 degrees if they are 4" or larger) and the temperature on the basking platform at around 90 degrees. Then the turtles will be motivated to get up and bask. The only way to tell what the temps are - water and basking area - is to measure with a thermometer. You can't tell just by feel.
Some turtles don't feel motivated unless the basking area is even warmer than 90 degrees. My turtle likes it in the low 90's.
We have to see photos to really know what's going on.
If your turtles haven't been basking then they may have a fungus infection. That's more common than bacteria though bacteria is also possible. If the spots are small and shallow they can be treated with sulfadiazine (brand name sulfadyne or SSD cream). It's only available by prescription from a vet.
To prevent shell infections, you are correct that you must get the turtles to bask frequently so that they dry out completely - top and bottom - under good UVB light. All the other elements of the habitat must also be healthy - clean water, good diet. Also, if your ph is high - much over 8, then it may help to lower it if you are having fungus problems.
SpotsMama