I did some research after converting my immersion chiller to counterflow and read a lot about how immersion chillers cool down the entire bath to a safe temperature where the cf chiller allows the batch to sit at high temperature longer while cooling small amounts. I used gravity to cool my first batch and had poor results. I bought a march pump even though I read 3/8 copper flow was a bit weak for my second batch with the cfc. I purchased the 815 model and I couldn't believe how fast it worked compared to gravity. I cooled 10 gallons in 7 minutes . If your 3/8 tubing and are concerned with using this pump, go for it,it has plenty of power. I should also add that I was pumping the wart from the ground into my conical fermenter.