I'm noticing some air bubbles coming out of return jets and am not sure whether this is an issue to be concerned with or not. Can somebody direct me about what tests I should do to try and isolate the problem or tell me if it warrants further research? The water level does not appear to be falling and pool water looks great. Water balance is also great, via Taylor test kit. I've already removed and lubed o-ring under glass lid in pump. I bleed off air from filter every day, which only takes a second. No obvious leaks in piping around pump or filter, except a tiny drip coming out of filter drain plug. I have a new o-ring for that plug I'm waiting to install as soon as I can get husband to remove it and then do a backwash. We've been enduring a lot of rain and I have excess water in pool right now. Final note, an end connector on 4-way ball valve just had to be replaced because it was cracked. No longer leaking but when it was, the air in filter took much longer to bleed off every day while I was waiting for the part. Could there be residual air in the system?