When I open the clear lid to my pump basket, all the water drains out and you can hear this “gurgling” sound as the water drains through somewhere (maybe the filter container??). Before I open the lid the basket is full of water with some bubbles at the top (we’re currently searching for a suction side leak). Just not sure if it’s normal that all the water drains out. We can hear it ”draining” for about 30 seconds.