Just got my first boat this year... 2006 Mobius XLV. Got a quick question about the ballast. With the main valve open, should the bags fill with water up to the lake level on their own? When I am sitting still, the bags will slightly fill with water, without turning the pump on. I thought the ballast pump would prevent water from entering the bags until it was turned on. Is there something I may be forgetting, or do you turn the main valve on and off everytime you want to use the ballast? Thanks for the help!