I think this is just typical manufacturing variances. I have two Nautilus tanks. One works very smooth and the bottom hardware unscrews easily from the tank. The other, I can still unscrew by hand, but it takes quite a bit of force. I'm pretty sure the issue is with the bottom hardware, as I have used this with the stock glass tank and the replacement glass and steel tank and they are both the same, and when you replace the glass tank with the glass and steel, you are also replacing the chimney in which the coil gets screwed into. Many times, when unscrewing this uncooperative bottom hardware, I actually end up unscrewing the coil from the bottom hardware (the bottom hardware is removed, but the coil is still screwed into the chimney).