That actually looks like a decent alternative for me as well. I've been through a few heaters due to fish tampering. I figured I'd solve that with a sump but then again, why spend the money on the heaters if I can run pipe to my water heater and use it instead? I don't have a water bill anyway because I live on a plot. I might as well enjoy my water heater a little more with something like this. Is the build very difficult? A whole lot of us try it yet?