Adding air to powerhead loop

[thecoolguy]

ok ..... simple question of powerheads/physics....

my powerhead (as many do) has an additional air tube (skinny)
which can be used to add air - and air bubbles - to the exhaust
if the cap is taken off

but now - even when i take the cap off - no air bubbles come out -
and instead, the air tube is partially filled with water

what is the process/procedure to once again make this air tube
functional?

[soulmia]

I had the same problem... and I am convinced that it is better to add an exteral air pump and have the bubble curtain producer (don't know what to call it!!) submerged in the substrate
This way you are sure that there is oxygen in the tank.
It may not be an answer to your question but this is what I have found acceptable and makes me sleep better in the night.

Hope you find a solution!

[Willyleigh]

The air may not be being sucked in because there is not enough water flowing past it, try to clean the powerhead, including the impeller to ensure easy rotation.