Piggy back ballast question

I have seen post on this in the past I just can't seem to find them now. I added the 750 piggy back system last year to my 2010 nautique 210 and rain fine tell this year. I have crushed my sending unit I guess due to negative pressure. Does anyone have any ideas to help with this. I talked to wake makers and they suggested I could try a t inline before and after the bags and add a check valve on the vent of the bag. The other idea they gave was to just run bags and that might have worked if they mentioned before I bought them so I could have ordered the larger bags. Any help is appreciated.