Am I right to assume that I can use an in-ground cartridge filter system on an above-groud pool? While just browsing through them, I have noticed that the above ground systems just seem small. I can get a much bigger one that's listed as in-ground. We are looking at pools in the 27ft by either 52' or 54' deep. Am I thinking right that the bigger square foot the filter is the less cleaning it may require? So would 175 sq ft cartridge filter be fine also? I don't mind cleaning, so I wondered if that would be sufficient?