Swimming pool heaters are rather expensive. Is there something safe to use that could replace one. For example, if I found a damaged jucuzzi, could that heater work to heat my pool? Also, why couldn't Ijust run really hot water into the pool about every 2 or 3 days. Or would that be just as costly?

Well it is kinda hard to draw the schematic out using abcdefghijklmnopqrstuvwxyz1234567890 on the keyboard. The drawing is in that book I referred to you and it is a quick easy to read and understand drawing. Plus the cool thing is at Borders you dont have to buy the book you can sit down and copy the drawing out of the book while you enjoy a cup of coffee. If you know a way for me to draw the answer out please let me know. I would be happy to drw this out and show you how to figure the answer to your question.