I use this brand for my skimmer. The vinegar bath will basically reset the break-in process. The plastic cover over the pump needs to be situated properly. The half circle holes should be opposite the pump output. One more thing you should check. The Venturi port that
@Hemmdog circled needs to be checked. When I first used my skimmer, there was a blockage in the port and my skimmer was doing the same thing. You should not see bubbles that low in the skimmer. Make sure that the hole connected to the tubing is not blocked.