Sorry Chris, bigger filters mean more time between filter cleaning and can help a bit with particulate filtration but they do nothing to add to the number of fish you can keep or the time between water changes. The fish capacity is rarely, I am tempted to say never, limited by the filter capacity. The real limits to water changes is how many fish you have and the number of fish you can keep is determined by how often and how big your water changes are. The build up of poisons in the water, including nitrates, are determined by how many fish you have, not how big the filter is. Particulate in the water column is another matter. Large filters with high flows will make the water look nicer as long as you don't get so much flow that you disturb the substrate. Heavily planted tanks also get a very small improvement in uniform dispersal of the fertilizers in the water column if you have extreme water flows. A healthy tank for fish can be maintained by a sponge filter driven by an air bubbler. The flow ratio in that tank will be less than 1x but the fish will thrive. Even with plants in the tank, you only need extreme flows if you are dosing huge amounts of ferts.