Although the unit he demonstrated was cobbled together for a
presentation at MACNA, it was relatively quiet (quieter than a
sump, quiter than the average overflow device and quieter than
a primary pump).
The exit pipe was longer as the unit was placed higher above
the tank and had a larger reservoir. ergo it delivered a
longer more powerful surge. Include an overflow in case the
flapper doesn't open.
Quite impressive. If you decide to build one use a 5 gallon paint
bucket instead of a pitcher (it holds more water and has more
room inside to work). Let me know, I would like to see the final
product.