With plenty of headspace, a strong back, and lots of vigorous shaking, a home-brewer can get levels as high as 8 ppm into the wort. This is about the maximum using air. Using an aquarium pump with a sintered stone will not result in more than 8 ppm, even with extended times. In fact, extended aeration can be detrimental to the head formation and retention. The only way to reach the recommended 10 ppm minimum is with the addition of oxygen. Filling the headspace of the fermentor and shaking vigorously can result in dissolved oxygen levels past 10 ppm, but once you have bottled oxygen, it is much easier to use a sintered stone.