I noticed the water level in my bubble counter is low (below the inlet stem) and there is water inside the inlet hose. I currently have my check valve downstream of the bubble counter (tank side). Should it be installed upstream of the bubble counter? Does the back siphoning indicate there is a leak somewhere? When I started to loosen the cap of the bubble counter, the water in the hose upstream rushed back into the BC and filled it up to where it was originally.