a419 johnson thermostat that is maxing out at 81 degrees. I have the sf set up to 90 degrees and it stays at 81-82 i have the probe sitting on top of my eco earth that i have in the tub I also have like an inch and a half of substrate in the tank. do you think that the substrate could be interfering? Im just kind of pissed off and dont know what else todo I know to some of you this could be a no brainer but I need to have my rack temps perfect for my new babys next week. thank you Brandon