Hello, this is my first questions since I just registered. I have a above ground pool with a Proline filter. I replace filter at the beginning of this season and I have a problem with the suction. The hose vibrates as it has in the past, but has a pull/push as it moves along. Also the Manta does not always stand flush with the bottom of the pool liner and gets hung up on the perimeter. In the past I don't remember the Return Flow Inlet being on and circulating water into pool with the manta working. I have tried the pump both on low and high.