2001 xstar - ski locker ballast filling even when pump is off

Hey there,

So I have a weird problem. I've noticed that when I empty the ski locker ballast tank in my xstar, I can still hear water dripping into the ski locker bag. I notice that when I close the input port at the back of the boat, I can no longer hear the water dripping into the tank. Anyways, I don't have this problem with the High Fly 750s that I have in the rear lockers. So I guess I have two questions:

#1 - how do I stop the water from coming into the ski locker bag when the pump is off. I'd like to be able to stop it from coming in without having to manually shut a valve everytime I finish using the boat.

#2 - since the rear ballast bags don't have this issue, there is obviously some valve or something that stops this water from coming in, and this has obviously failed on the ski locker ballast. Can anyone tell me what stops this water from coming in, or tell me how this works?

Thanks much!