Thanks Brian! That was very helpful and answered some other questions I had regarding temp fluctuations. I couldn't quite tell if that was a 6qt tub or a 12qt tub you were using. I would assume the size of tub is important to keep the right amount of substrate at the bottom. I've seen people refer to both of these size tubs as shoe boxes, so I just want to be sure which to use with this formula. Thanks again everyone for your responses!