I bought 2 of these with heatsinks. They cool water and I tried one in a 5 gal DWC system. At first it did not work, because the heat sink was to small to give my the right temps. bought a 12v dc pump and a big heat sink and it keeps my temp in the bucket 55 to 58 all the time. I bought a temp adjusting thing that is advertised with it. It seems to work good. I paid 30 bucks or so for all of it. I was wondering if anyone else tried this, instead of a high dollar chiller?