Pump puzzle
 

I'm running a Blueline 100hd return pump (1900gph) and had a tee to a manifold to feed my various reactors.
After doing a recirc mod to a CS8-3 I supplied it from the tee as well.
When I diverted too much water from return, it started blowing air bubbles into the tank.
I just can't figure out where the air was coming from. I'm thinking it's some part of fluid mechanics and I must have skipped out that day.:smile:
I've since added a separate Turbo Sea pump to run all the aux equipment and all is good (except the power bill) but I'm still puzzled where the air came from.

Thanks

Silly question I know, but if any of the new plumbing is going up and then down you will certainly trap air in there and it will be forever before it is evacuated.

No they are pretty straight runs, everything would working fine but if I opened the valve to the skimmer past a certain point it started blowing bubbles to the main tank. From a hose barb on the teed line to the skimmer is about 24" of clear hose so no trapped air there.

Pics would be helpful.