I have a gunite pool and spa that was installed in March 2016. The spa jets worked fine for the first few uses but then one jet outlet began sucking. Then this jet started working fine. Now 2 jets are sucking. There are six jet outlets, 2 water inlets (for hot water to pump in), 1 air intake in the coping ledge. 2 Jets are sucking and 4 are blowing great. Any ideas what my problem may be?