Are you seeing air bubbles in the basket once it's primed and running? If not, then it's pretty minor air leak. One way to check if you're getting air is when the pump is running/water flowing, is to run a steady stream of water over all the fittings, and see if the air in the basket goes away (it will suck in the water/not the air) and will narrow down which fitting. You can also use foaming type shaving cream.