I bought a used intex 2650 and not ready to succomb to the fact that i was ripped off yet......plugged in and set up but when i turn it on, it sounds like it's on but it's just humming, nothing is pumping/circulating.....i'm sure what to do. Seller said it was in good shape and ready to go......just frustrated. bought my intex 18x48 a month ago and have spent only a few days in it.