SS Brewtech 20 Gal Mash tun has no problem with 42lb of grain and I can get a 1.070 with a 20 gallon batch with a 13 gallon mash in and a spare of around 12 gallons.
I have this SS Brewtech 20Gallon Mash tun and with my herms system I heat it with 11 gallons the night before my brew to 160 degrees. I find it only losses about 10 degrees over night. When I wake I turn the HLT to my desired temp and add my grain. This shortens my brew day by a few hours.
Is it ok to use a Home Depot plastic cord grip to hold a K-type temp probe in a T fitting on the whirlpool recirc loop before the ball valve of the HLT?