Please note my terrible MS Paint visual below.
If the water level drops below the connector on the hose itself I hear gurgling and air gets into my pump and I lose the prime. The obvious answer to me was 'faulty hose', but I have bought 2 new ones...so I have gone 3 for 3 with this issue and I am frustrated.
I have to keep my water level very high, over the top of the hose assembly connector, in order to vaccuum. Keeping the water level high makes the skimmer pointless, as the water level is above the skimmer intake. If I vaccuum to waste then I only get 10 mins or so before I can't anymore...then have to refill pool with garden hose for an hour to start again.