I've rigged up a counterflow chiller which gets wort down to about 5C above groundwater in 1 pass. Now my tap water is about 25 at the moment so this means i'm only getting it to about 30C. I have a stainless coil (about 12m left) from an immersion chiller that I hacked up and am planning to use it in a bucket of ice water. Would it be more effective if i ran the 30C wort through it after it exits the counterflow chiller, or run the tap water through it before it goes into the CFC to give the CFC better cooling capacity? I do minimum 40L batches and it takes a while in the fridge to go from 30 to 18 to pitch.