I tried water pumping with the traditional air tube and pump, and did not see any advantage.
I have a 9” x 1.75 cylinder that I normally pack up to 7.5-7.75”. That leaves barely enough space for about an inch of water and an inch of air space at the top for pumping.
So what is the effect of that measly 1 inch of water in my tube?
I just find it an enormous pain in the ass preventing it from getting sucked into the pump.