welcome to hho! cooling systems are the easy part. The best i've found after testing a ton of ideas. a couple stainless steel tubes going through both sides of the container attached to a small radiator or trans cooler with high temp hose. pump fresh water or 50/50 tap+antifreeze at the speed that gives you the ideal temp. your unit and cooling system will last forever. Wish i'd take some time and upload my setup. I do have my little hho cutting torch posted. check it out. good luck.