Difference between AG and IG filters?

[sunlove]

I googled my question, and read that the difference is that an inground filter is supposed to be installed above the water and the above ground filters are designed to be installed below it. So it seems that doing the opposite would have an affect on the performance...yeah? So if this is true that knocks out a lot of filters I was considering And I discovered my pump is rated for 50gpm.

I emailed Hayward and they are suggesting this filter ...what do you all think? Anyone using this one? I don't want to be undersized again but don't want to buy more filter than I need either.

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Manufacturer: Hayward
Model: C550

These high-quality filters are designed specifically for use with aboveground pools. Manufactured from high-density ABS materials, these filters are designed to provide years of trouble-free operation. Micro-Clear filters are mounted on a rugged filter base and use a special reinforced polyester cartridge engineered to provide superior water clarity with minimal care.

For Above-ground pools
Easy-Lok™ lid design makes it easy to access and service the cartridge element
Built-in check valve prevents accidental loss of pool water when cartridge is being removed for cleaning
Unique safety-catch prevents over tightening of the cover and unwanted entry into the filter
Cartridge element is uniquely designed of high quality reinforced polyester and a molded center core for easy cleaning, high flows and long life. (Filter includes cartridge)
Union connection allows pump or filter to be removed quickly and easily for servicing systems
Dimensions: 8 3/8" w x 24 1/2" h
Effective Filtration Area: 55 ft; Design Flow Rate: 69 GPM; Turnover (In Gallons): 33,120 in 8 hours and 41,400 in 10 hours
Warranty-1 Year