Jane thanks for update. Crumbs, Hubby seems to have thought and tried everything.
Andy – Explaining Boyles Law is akin to the offside rule in football for me. Also agree with Jane’s Hubby keep it simple. Your right Bubbles get bigger as they rise.

The method that bests uses gravity in its purest form (push/pull) ought to be the most efficient. Though in this case, it’s not quite that straight forward. I would have assumed the best method would have been the pull...... Did Hubby try the push Jane? Would be really interested to read more from estanque_koi (Diego) and Jose Frutos - why they opted for the push method? Did he have a theory/reason or just followed a train of thought which on re-reading the thread again seems to be the case? Hope either can reply when not too busy.
Jane, I appreciate/accept Hubby needs air stones to regulate the flow from the air pump.
A while back on another thread we were reviewing the most efficient pumps -v- so called claimed electricity usage. This included whether we could generate additional power, a dual use, from the pumped water returning to our ponds. I contacted several Professors to see if micro/nano paddles would work as a secondary power source and in short they all repeated the same thing back to me in the simplest form –‘ There are no free lunches’. Technically it could work though by increasing the pumps work rate or using a stronger pump defeats the object of the exercise.
Returning back to air lifts swiftly, the air pumps current purpose is to the move water, a secondary aspect is the oxidation. Given the enormous energy savings why has no one developed this concept further? I’m half way through a pond build and thinking what I ought to be doing now in preparation for making air lifts later. No free lunches indeed... there’s one in the eye to the Academics.
Regards,
TicToc