If you find, after filling your bag or after the sand has settled, that your bag bulges on the bottom or rocks when on the bench try the following: Bang the bag flat down on the bench then gently slide it into place. Slapping the bag firmly onto the bench shifts the sand back up into the body of the bag and flattens the base of the bag. By pushing - rather than lifting - the bag into place, the bag will maintain that flat base.
You may also find that using one of our Dead Bottoms (located on our Catalog Page) will help to correct the bottom "bulge" and create a flat surface to stabilize the bag. Note that the dead bottom will raise the bag approximately 3/4".