Esshup,
I think I'll pass for the reasons JKB said, and the fact that I need at least 4 watts per gallon of water for a 9 degree temperature increase in the tank. That means for my 330 gallon system I would need 330 X 4 = 1320 watts to bring the water up to 71 F. and hold it there.
I'd like to eventually get a commercial size submerged heater from AES to do the job but right now money is really tight.
Money well spent would be to insulate and heat the atmosphere. Water temps would only be about 2-3 degrees cooler than the ambient air temps. Everyone that thinks they can just heat water will always loose. By far, more energy wasted. You have to think of terms of saturation when it comes to temps. Keep it as even as possible.
One thing you may not know is that every engineering equation, regarding raising fish, has Temperature in it. That should be a flag.
