Think of your filter as the vacuum cleaner bag, the larger the bag the more dirt it will hold before clogging and having to be emptied or replaced. A larger filter actually reduces "head" and allows more water to flow for a longer period of time. Longer filtration cycles = less work. A 48 or even 60 sq. ft. filter would be a good choice. Pentair makes 80 and 100 sq. ft. models that use modular cartridge-type "grids" that would work very well. They are a stronger material than that used in most D.E. filters and seem to clean much better when it is time.