I use 2 of the Coleman 70 QT extreme coolers, one for my HLT and one for my mash tun. I have them on a sturdy shelf on the back wall of my garage, HLT over the mash tun. I use a pump to pump the mash water into the mash tun and the sparge water into the HLT. I have a ball valve on the HLT to drain the sparge water into the mash tun. This works really well for me. The pump saved me from having to buy another burner and an expensive stainless steel HLT. And it multi-tasks: The pump is handy for batch sparging and for chilling as well. The over/under configuration on the wall (shelving is heavy duty and mounted into studs) makes for a very small footprint, too.