Is there any reason why an In Ground Pool Filter cannot be used with an AG Pool? I have a 30K gal. AG Pool and can't find Cartridge Filters big enough for my pool that would keep me from cleaning cartridges way too often. I have found a fewould not work in my AG w filters that interest me that are 425 and 525 sq. ft. but they are advertised as In Ground. What would be the problem with using one of these in an AG application?