Make Your Own "Diffuser":

A diffuser will literally diffuse and filter more air thruogh the water

Will make tinier bubbles and hardly any noise with more pull.

Take around 3-5 plastic BENDING straws and put in bottom of shaft without bending them.
Add water.

As you put them in the water bowl, they will bend out in all directions and if they are not cut too short or too long will each touch the sides of the bowl in different places, adding filtering and diffusing extemely well.