Please help, I have an aquaclear 70 on one of my tanks and I am having non stop problems with the filter. The motor keeps quitting on me. I have had had a number of aquaclear a over the years and have never had any issues but this is getting very frustrating. I have taken the motor off a number of times, clean it all out and I have even applied Vaseline on the magnet to grease it. No matter what I try, I can't keep the motor running. When I plug it in it will fire up for a few seconds then cuts out. If I give the impeller a little touch it will fire up again but it quits a few seconds later. I do have sand in the tank, can that be a cause of my issues? Please give me any advice, I can't keep this thing running.