Hello everyone.I have just taken my Nullarbor A32752SL over the pits and was asked to drain the fresh water tanks prior to weighing the vehicle.Problem is only tank1 would drain all the way and I thought tank2 would kick in automatically and drain as well.All that happened was the pump was spitting out more air than water.Any ideas as to what I have done wrong would be greatly appreciated...Thanks in advance Mark from down under.