Originally Posted by ib4classics

You probably ran water from the faucets in the trailer to purge the antifreez, that water went into your "gray"water holding tank.
Drain the gray water holding tank and see if the status board shows empty.
There may also be debris on the sensors in the gray water holding tank which could cause a false reading.
Filling the gray waer holding tank with water and bleach, let it soak, then drain may solve that problem.