Bubbles in dosing lines

[Psychonaut]

Can someone please help me get to the bubbles in my dosing lines?
I’ve primed them obviously to get all the bubbles out but every night I come home from work there are more

I made sure all the dosing containers could let air in, and I zip tied all the connections.

Always on the outgoing side, close to the pump. Thanks

 

[Retro Reefer]

Try running high quality one way valves on the output ends of your dosing tubes.

 

[Psychonaut]

Like all the way at the end? The last thing the liquid touches before it drops into the tank?

 

[Retro Reefer]

Yes