I'd say I'm using roughly 3 gallons (volume, not actual liquid) of ice inside the bucket housing the copper coil. The coil is 10' of copper I believe (can't remember, but it was $13 at home depot). The pipe is 1/2". If you pour the wort (at almost boiling temps) at a steady slow pace, giving just a couple seconds of cooling time every once in a while, the wort comes out at maybe 75-80 deg. I noticed if I poured too fast that it came out really hot, but if you give it a little time then the wort chilled just fine. Honestly, with everything I was reading, I cannot believe that it chilled that fast. I'm wondering if I just stumbled on something great or if it's too good to be true.