My smokey lake pans have the same round passage between channels, i don't However get the niter build up that you are describing, i have a 30"×30" syrup pan, i can normally make about 50 gallons early season, and 20 or so later in the season before it need a quick cleaning. Usually my niter forms from the draw off point and will continue to format further away from drawoff point until I clean it, maybe you are batching a little to much instead of having lots of smaller draws?
Nate Hutchins
Nate & Kate's Maple
2018 1000 taps?
20x36 sugarhouse
CDL 600gph RO
Franken evaporator, lapierre arch, smokylake pans and a leader hood with pre-heater.
A wife and 2 kids.