I have a melamine 5-level rack, with flexwatt heat tape and a herpstat thermostat. The herpstat is currently set at 99.7, and temperatures are still reading 80 on the warm side! It's really cold outside, so I know that's affecting things now - but even before it got cold, I was having to keep it set between 95-97 to get close to warm enough. Anyone else have this problem, and/or suggestions on getting more effective heat?