If I could justify the cost, I would switch from the Intex cartridge filter I have to either sand or DE, preferably DE.

There are pro's and con's for each type. From what I've read here, the sand filter is probably the lowest maintenance of them. Once you have the sand in and working properly, you almost never have to replace. DE filters require new media every time you backwash, and carts require removal for cleaning, and yearly replacement.

YMMV depending on your circumstances.