Now having said that, I am still careful about where I place it, especially if I want to use it with ants that I have in test tube setups. For test tubes, I will typically place it under the cotton at the opening of the test tube. Others place it on the water end, but warming the water end seems to allow more mold to grow on the cotton at the water end.
For formicariums, I just place it through the heat cable tunnel and that's that. There is enough space that the ants can decide where to place brood, where to relax for an afternoon nap, etc.
