Grey water tanks

[jvbutter01]

Hello all,
1st trip, we took we only used the sink's and toilet. Grey tank 1 was filling up, never full on gauge. Got home, pulled the 1 grey tank valve. Empty.

2nd trip we took we used sinks and shower. While in shower, water was backing up. We checked the tank 1 level, full. Tank 2 Empty. I went outside, pulled the 1 grey line and emptied the tank 1.

What fills grey2?

2020 2900RLWE Keystone Passport

[mfifield01]

You probably only have one Gray tank. I had two lights on my Passport, but only one tank. They make the control panel generic, so other Passport models with two tanks can use it as well.

[jvbutter01]

This would make sense. I was on city water the 2nd time, so its well possible that the tank was filled from so much city water usage. We were only there 3 days, but I didn't monitor it as should. I will have to test this again and see what happens. I will be adding a battery monitor soon. I will be dropping down the "Season Extender" cover under the trailer to run wires. I will see how many tanks at that time.