Hi John, thank you for such an in-depth reply. As you said, there is a lot to think about. Several points you made hit the spot right away, especially about the north facing long side and having the mass above ground. I have been looking into using water as an added part to the thermal mass, and you are on the button as I would be reaching to maintain the 72deg that I would need and maintain it. I am going to study all that you have said, and go for the book as you suggested. Gosh, and I thought it looked fairly easy! Well, I am going to get into this and will come back to you as things progress, and especially if I run into something that I can't fathom. I had a thought during the night that I could perhaps shorten the run by going down the middle instead of the sides, and having the grow beds in the middle partially over the mass at both sides, with the fish tank at one end and with the heater at the other?. I didn't sleep long as you can imagine. I am going to plan this well, and with your help and the information from the book, I should be well armed. Thank you so much John, I am sure to be back, but your equations really jump out at me and help a lot.
