I just got an Emp 280 and it's now set up and running on the lowest flow setting. My problem is that when I push the flow adjuster down (to increase the flow rate), the water level in the media basket begins to drow and the pump makes loud vibrating and gurgling noise like when I first primed the pump. The gray adjuster I am pushing increases the flow of the spray bar, but it must not increase the flow of the main intake pump, this would explain why the water level drops. Is there an adjuster for the main pump? How can I turn up the flow rate with out the water level dropping and without the noise? Thanks.