After you flush my toilet in the tank it makes a slurping noise.. like when you slurp up the last bit of your drink with your straw. The water level is lower in the slurping tank, but I am not sure what is causing the tank to no fill up. If we put more water in the tank by hand the slurping stops.

If you replace the "flapper" valve in your tank the system should work more efficiently without the "slurping" sound and the necessisity for adding water to the tank.

Which ballcock is yours?(see images)

First respond Tom and we will go from there, Thanks.

John