Homebrew PCBs

Hi,


What else could one use as air pump for bubble agitation?
Because i had so little bubble holes bubbling i connected a rubber ball  
(with one-way valves) instead of the pump.
Surprisingly the bubbler hose works really well if i compress the ball by  
hand. The small aquarium pump just doesn't have enough pressure or flow to  
operate enough of the holes to create a even curtain.


Now i'm looking for a larger pump. There are cheap piston compressors, but  
because i want to run the thing closed loop (take the air from inside the  
etching tank) they are unsuitable with their aluminum cylinder.
I thought about buying a 10 piece lot of small pumps, and connecting them  
together (maybe some series some parallel) to increase the airflow. You  
think that would work?

Any other ideas welcome, i just can't come up with a solution.


ST