Why constantly soak in cold water when there's heat.

[RandyRhoads]

Finally got my Burms new cage. 8' by 3' by 2.5'. Really like it. I have a good sized tub of water at one end, and at the other is a heat pad and a heat lamp. The heat pad goes on at night and light during the day.

The surface temp of the heat pad is 101 F and as you travel to the other end the surface temps rapidly decline to about 75 throughout the rest of the tank.

With the heat lamp, directly under it is 140 F, the middle of the enclose is about 85 and the other end is 75. I know 140F is too hot for her but 1 foot away it's 85 so does it need to be lowered?

The ambient temperature is always about 70 throughout. Does ambient matter or just surface temps? Can someone explain the differences( I know what they are, just not the importance of each seperately)

I don't understand why she is always at the cool end in water that 68 F. Could it be because there are no hides and she's just in there for security? I'm working on making a hide now but curious why she's in cold water rather than in the zones with ideal temps. It's not a shedding or mite issue. I know she doesn't have mites. And she soaked before shedding (as usual) but continues soaking still even though she has already shed.