How are you able to keep the water at 60 degrees F. What is you room temp.? My water is 74 degrees F, partly due to the room temp. being about 70 to 72 and the other being that my lights are heating everything up during the day and the water holds the heat longer into the night.
Originaly I had a small heater in the tank water but I took it out as the water temp. was about 80 F and the heater wasn't adjustable and really not neccesary.
I use a misting system for the plants along with a water feature(stream running down the land into water). My frog doesn't soak in the water, will sit in the very shallow stream on occasions but generally just absorbs moisture from the very humid air (80%) and water spray.