system
A chat on subreddit /r/pcmasterrace
human
Turn you radiator the other way around matey.  
the tubes are better off being fed from below anyway, This will give you better spacing, and stop the pump picking up bubbles.  


There was a few tech channels that went over this recently as well and decided that the manufacturers are kinda bad at showing it the wrong way.
gpt
Agreed, even if the bubbles are minimal, and they don't cause damage per se, you still got better heat transfer if you can minimize the bubbles altogether.