I bought a foam cooler to hold my coolant(ice water), as I have easy (free) access to both water and ice. Once I had it all hooked up, with one tube going from the pump into the heat exchanger, and another from the heat exchanger back to the cooler, I submerged the pump and plugged it in. At this point you'll be able to tell whether or not you have leaks real quick. If you do, just shut it off and tighten things up. If you've got a hole in your copper tubing from over-zealous bending, you might have a tricky problem to solve. I didn't have that problem, so I couldn't begin to tell you how to solve it. (I am partial to JB Weld for all things broken though) I've noticed that towards the end of the copper tubing, I'm not getting any condensation, which means by the end, the water has lost it's cooling effect. When I get a bigger pump, the water will flow much faster, and hopefully won't warm up as much. Well, that's about it, any suggestions would be welcome!