newb question: keeping water at correct temps

[stuartambient]

just starting out here with a letter raft / bubbleponics type of system. Finally finished all the hardware, but filled the res with a few gallons of water and it's been sitting unaltered for soon approaching 24 hours. I was really testing for leakage but what I found is that the temperature of the water is way too cold. I need to get a thermometer but it's way colder then when I filled it. This from sitting in a room that is fairly small, fairly tight with a duct register in the room. Our thermostat is I believe set to 63F.

The lights were not over the setup, but I'm running FS cfl's (= 500w / real 110w) still doubt that would heat the water. So what is a good way to heat the water. I think aquarium heaters might work though it's Roughmate tote so I have no idea about the safety.

Any ideas ?