I have been playing around with the timing for how long to turn on the air pumps (as well as the delay time between bubbles). This video is my “favorite” so far for the solid bubbles (on the left) 30ms on-time, and 300ms delay. Obviously, the aquarium air stone tube (right side) needs a longer delay to separate the air pulses.

Of course, I also tried playing around with super fast bubbles!

And with the smallest bubbles I could make (the electronics can give a 1ms pulse, but the motor/air-pump needs at least 8ms of power to eject a bubble…)