I have northern brewer's version, the Chillzilla. It works great. I brew 15 gallon batches and recirculate/whirlpool until I get below 140F. It usually takes about 10-15 minutes to get down below 140F. Then I cut the pump off and let it sit for about 10-15 minutes to let a trub cone form. After that, I crank up the flow on the chilling water and it chills down to 65-70 with a chugger pump running wide open into the fermenter. In the summertime, my tap water gets warm and I use a immersion prechiller in a small kettle of icewater.