I’ve never cleaned out my trays mid grow. Only time I mess with the trays is if the autovalve becomes blocked, but usually a 60ml syringe full of fluid blown through the line will unblock it.Got a ???? When it's time for a rez change do you also empty the autopot tray I would think so since it getting a fresh supply of nutes and it's a way to see if the aquavalve still working like it's suppose to???