Ballast vacuum

I have sacks plumbed on top of all 3 tanks on my 06 Nautique 220. When I drain the ballast, the pumps create a vacuum that pull water through the sacks into the tanks, and then empty out of the tanks. I am having a problem with the sacks completely flattening once they are empty and forming a vacuum which doesnt allow air to pass into the tanks to replace the water when they start to empty. It keeps causing my pumps to flip the breakers.

Has anyone else experienced this type of problem? Any thoughts on a solution? I was thinking of adding a straw of one sort or another in the bag itself to keep it from vacuum locking...