NEVER dirty the water in a CAMERA dunk tank with your mask. NEVER EVER EVER put anything but a CAMERA in the CAMERA tank. Rinsing your mask there will earn you enemies, and for good reason, dirt in that water could result in dirt in orings, which could cause a leak that would ruin hundresds of dollars of gear.
Also, rinse your mask out in theo cean to get out scuba-cicles/snotcicles before rinsing it in the mask rinse tank.