In command JRVCS1

[Paul B]

I just bought a 2017 Raptor model 355 TS with two bathrooms and the Jensen in command monitoring system. I have two black water holding tanks. I am trying to determine which holding tank (1 or 2) on the in command monitor is the primary tank. Thank you.

[OregonDuck]

One might assume it would be #1... I'd just add water to one tank until it reaches 1/4 on the monitor and then you'll know.