This is where I'm lost. Let's say I have 4 gal of wort in MLT recirculating via heating coil in HLT maintaining at 151F. After 60 mins, while pumping those 4 gal of wort out of MLT to BK, I need to pump in 3 gal of hot water (170F) to MLT for fly sparge. Where do I heat those 3 gal of water? Do...