Then the person was a moron, or the garden center sucks, take your pick. Try going back and talking with someone else, if they still don't know what your talking about just buy it online, it's very light weight so it's not too expensive to ship and you usually don't need a lot of it. Oh and don't get the shultz brand, it's not sorted or sifted so a lot of it is like sand and can cause more issues then solutions... plus they over-charge for it. Hope that helps.