Air in submerged DIY pond filter?

[DerSchoeneBahnhof]

I built a DIY pond filter, following a design from a YouTube video:

My design:

Once in a while the container fills up with too much air and starts tilting. I already put bricks on top of it and some bricks inside.

Any suggestions to relieve air inside the container? Have a separate pipe going higher than the water level (or would that make it worse)? Another thing I thought about is to shut it down every day on a timer for a short amount of time since I noticed when turning off the pump, air seems to bubble up to the surface.

Just fishing for some ideas
CG

 

[Mmathis]

Maybe drill more holes in the top.

 

[DerSchoeneBahnhof]

Maybe drill more holes in the top.

Definitely, I drilled more holes yesterday in the lid. Will see if it helps. I have to cover the holes with plastic mesh though as the smaller fish may get inside otherwise . Don't know if the mesh impairs air flow.

 

[Dave Cee]

Back in my larger-pond days my pre-filter would tend to float off the bottom every couple of weeks or so which was a signal to me that the filter pads were full of "solids" and needed cleaning. I would simply rinse the pads off in a bucket of pond water and good to go. The bucket of "solids" was appreciated by my various yard plants.
Just rinse out your bio media with pond water once in awhile and rock on.
I also used a couple of heavy stones to hold the pre-filter down between cleanings.
Best wishes. Dave

 

[Mmathis]

Definitely, I drilled more holes yesterday in the lid. Will see if it helps. I have to cover the holes with plastic mesh though as the smaller fish may get inside otherwise . Don't know if the mesh impairs air flow.

In general, fish won’t be sucked into the holes.

 

[DerSchoeneBahnhof]

Back in my larger-pond days my pre-filter would tend to float off the bottom every couple of weeks or so which was a signal to me that the filter pads were full of "solids" and needed cleaning. I would simply rinse the pads off in a bucket of pond water and good to go. The bucket of "solids" was appreciated by my various yard plants.
Just rinse out your bio media with pond water once in awhile and rock on.
I also used a couple of heavy stones to hold the pre-filter down between cleanings.
Best wishes. Dave

Got it about cleaning, but this happened a day after I cleaned the poly-fil quilt batting Maybe I was trying to be too smart and had removed stones on top, just had 2 bricks inside the container.

I put 2 more bricks on top (in addition to drilling more holes in the lid) and it hasn't flipped again this week. I'll try to add more bricks and hang them to the trash can handles or something.

I guess it's what you call iterative development

Best,
CG

 

[DerSchoeneBahnhof]

In general, fish won’t be sucked into the holes.

I hope so, but small branches / leaves might.

I have seen fish going through the holes in the milk crates supporting the plants though