Actually, I kept watching the returns after running the pump at 3000 rpm for 15-20 minutes and noticed the bubbles kept coming out. They are very tiny bubbles and not "shot" out of the return. Rather they just float along the wall where the return is. Very intermittent, sometimes I have to wait 10-30 seconds to see another group of bubbles. I also noticed that they come out of only one return, whose water flow is stronger than the other return's.

Does this mean the air trapped in the pump basket is slowly being pushed out and thus a good thing? Or does this merely indicate air is slowly entering into the system? I tried to look into the pump basket to see any bubbles coming from the suction but it was difficult to see inside (the lid not as transparent as I would want it to be and also air pockets made it harder).

I think I am okay even if the pump doesn't fully prime as long as it stays that way and I don't need to re-prime the pump. But I'll have to fix any air leaks.

Thanks a lot.