I have a 08 lsv that came with the gravity 3 system--rear bags are 400lb's. I bought a 750lb to use when surfing. What i do right now is just use the bigger bag only for surfing. What im wondering is can i use the 400lb bag using the boat ballast pump and then set the 750lb on top of it and use my tsunami pump to fill it and empty. I would end up with around 1050-1150lbs of surf ballast that way.

Any body see any concerns doing this or any thoughts??