when i fired up my pool this year I had a horribile vibration sound coming from the heater. At first I thought it was the heater however I noticed the water in pipe is shaking pretty bad that comes out of the jacuzzi filter and feeds the heater.... still thought it might be the heater "perhaps a valve blocking water flow" however when I grabbed the lever on top of the sand filter and applied a little pressure down the noise totally stopped. Wondering if anybody has any experience with that.... Do I have a faulty sand filter or is it the heater...