Could I just plug the drain line from the inside of the tub, and get the water out of the moto massage section some other way when I clean it? Or is that also a fill line? Thanks for the help, and I bet you are right about the leak update: not sure if this confirms, but in my mind it does:) I filled just the moto massage compartment with green food coloring and water. You could clearly see the water draining out of the box, and within 10 minutes the food colored water showed up in the foam under the moto section. My guess is there is a crack, because when I opened the line drain green water also came out. Does this make sense?