How is air getting into my filter?

[BassetsForBrown]

I have a Cascade canister filter. It doesn't leak water, but it has daily episodes were it blows air from the output. (No, the air pump isn't near the filter intake) For some reason, this seems to happen more often at night.

Somehow air is getting into the filter. What might be causing this?

 

[duanes]

Cavitation is a possibility.
If the impeller is even slightly off, wobbles, (or wear, from a grain of sand in the wrong place, etc etc it can cause cavitation, where air bubbles collapse out of the water.
If left unchecked the bubbles can pit and ruin an impeller.
In the water industry, it can even ruin steel impellers
Cavitation - Wikipediahttps://en.wikipedia.org › wiki › Cavitation

 

[Rocksor]

Does your filter leak water if you turn it off? Leave it off for 30 minutes and then wipe down around it using a paper towel to check for leaks.

 

[BassetsForBrown]

Does your filter leak water if you turn it off? Leave it off for 30 minutes and then wipe down around it using a paper towel to check for leaks.

I'll try and see