Abstract: A plurality of balloons are disposed inside a liquid container to take up space as liquid is removed from the container. The balloons can be connected to a gas injection system to inject gas into the balloons to keep the liquid fill level in the container to a filled level. This results in little or no sloshing of the liquid inside the container. The balloons can be secured in place by one or more positioning boxes disposed along the container's inside periphery. One or more strings can interconnect the balloons to the positioning boxes.