How to quiet down the ziss filter

I had originally tried two other things;
1- added a very fine sponge just above where the bubbles release inside the ziss above rhe course sponge to try to make bubbles smaller, but this was futile.
2- I also tried to find the minimum air i can push go through. I aimed the air to one side of the tube by blocking half the opening at the bottom, which got things moving easier but it was still too noisy.

So forget all the troubles, just skip to my final solution -the sponge on top. I try to keep my water level high so it hides the sponge, but over time it got filled with algae and looked natural. I found that the sponge dispurses out the bubbles causing significantly less noises and it aids as a sponge filter.

Ive seen others say the ziss doesn't make noise for them, but I suspect that their tanks are well covered and the fish are ones getting all the noise.

Over all, i would never use this in a normal tank setup. This is best for a bare tank where you can vacuum often cause this just doesn't suck up anything but water.

filter