As far as I know, Quikrete doesn't bag or sell filter sand. They DO sell both play sand and masonry sand. Masonry sand would do a great job of filtering . . . until the fines clogged your laterals, and tore up your multiport valve. Since that hasn't happened, I'm guessing you bought play sand, which is much too coarse, and would result in poor filtration, but low filter pressures.
Yes, you probably should change the sand.
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