how much water?

Going to install a couple ballast bags in the bow compartments of my Cobalt. Would like to ensure that I get the same amount of water in each as I probably wont fill them completely. Does anyone know of a meter that can be installed in the fill line to tell me how much water I have pumped into each bag?

go by the list of you boat. them being filled equally is irrelevant if your boat is level

plumb the bags together. that way they're always even. you may just need one line between them, but I would also T the fill line if I were you.