I just got an interlocking backyard patio installed. The contractor was supposed to use polymeric sand, but I believe they lied and used regular sand and just told us it was polymeric. They didn't even spray the stone with water - I had to do it myself. Is there an easy way to tell without a doubt if it is really polymeric sand? There is also some left over in a container, if there is a way to test it using water or something. Thanks.