The two tanks are joined at the bottom. There is no valve and the water flows between them.
Calculate it as though it was one tank, pour the diluted bleach solution into the fresh water fill, and then fill up through the fresh water fill. Then run your pump and open faucets to run the sanitizing solution though the system.
Sherm & Terry w/rescues Steve (std Poodle) & Eydie (min Schnauzer)
2015 Jay Flight 27RLS (Camped: 102 nights 2015, 90 nights 2016)
2006 Ford F350 6.0 PSD, Lariat, 4WD, CC, LB, SRW, auto., Camper pkg.