Pretty easy once I got all the parts together. Assembled it all over the course of one night. Hardest part was drilling the hole into the side of the hotel pan for the water heater. Luckily my neighbor is an electrician and had a step bit that worked perfectly, took about 45 minutes.
Oh, and the Radio Shack relay mentioned didn't work for me when hooked up to my PID's solid state relay (different PID then used in the link). The switching voltage wasn't enough but eventually got a relay that only needed 5V to switch. Short term I used the internal relay which worked fine, but was noisy and I wasn't comfortable driving that amount of amperage through it.
By using beer cooler, you can reduce the heat output required to maintain a constant temperature. I also wonder if one could substitute a mixer or model boat propeller on the end of a rod and a small motor for the pump?
Oh, and the Radio Shack relay mentioned didn't work for me when hooked up to my PID's solid state relay (different PID then used in the link). The switching voltage wasn't enough but eventually got a relay that only needed 5V to switch. Short term I used the internal relay which worked fine, but was noisy and I wasn't comfortable driving that amount of amperage through it.