We have a worm farm to raise earth worms to feed our koi.(100 percent
protein)
Our fish love them. How big are your fish? Ours are big so they can
manage a big worm. You'll have to cut your worms up if your fish are
small. We also water all our plants and flowers with the muck/sludge
from the filters.

I'm not sure if you're asking a question but earthworms getting into filters and ponds isn't unusual, not super common, but not unheard of. I've only seen in filters mounded in the ground so the worms can travel along the ground and fall into the filter under the lid.

If you're asking for suggestions on how often to clean the media...you're not going to like this but here goes...

Activated carbon does indeed remove small bits of stuff. Used in drinking water filters. Just like drinking water filters the activated carbon only lasts so long because it becomes clogged with trapped particles. In drinking water systems the activated carbon is placed as the very last stage, after reverse osmosis. That's because they want the activated carbon to only get super clean water so it doesn't clog as fast.

In a pond environment activated carbon would clog in seconds, maybe minutes. You won't notice any change because stuff that clogs activated carbon is too small to see, sub-micron, smaller than bacteria.

So I wouldn't worry about cleaning the activated carbon. I'd throw it out.

The mesh and scrubbies are called static submerged media...at least I assume they're below water. These are OK as a pre-filter to protect a pump, catch leaves and large stuff. In that case you just clean them when clogged. It's fine to rinse with chlorinated water if you like.

However, if these media is intended as bio filter media there is a problem. Any bio media that ever has to be cleaned is not actually bio media at least for growing bacteria that consume ammonia and nitrite. These bacteria need media that stay clean otherwise they can get to the ammonia, O2, carbon and stuff they need. Here's a picture of what the bacteria look like:
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The black dots are the bacteria and the gray structures are the bio film (jelly like stuff) the bacteria produce to anchor themselves and get up into moving water. In static submerged media that has to be cleaned means dirt can collect on the media. The fins are very small as you can imagine. It takes almost no dirt to clog those structures. There will be some areas that stay clear, so this media can grow some of these kinds of bacteria, but not much. A lot more will being growing on the inside of the pump pipe/hose because the flow is so intense it helps keep the bio film clean.

So there's no good answer for how often this kind of media has to be clean to function as a good bio filter. If you wanted it to perform more like a Trickle Tower, Moving Bed or Bakki Shower you'd have to clean the media every hour maybe. Those filters are self cleaning which is why they perform so much better. But no one of course is going to clean media every hour, that's crazy.

Beyond that you're into a Catch-22. As dirt clogs the bio film the ammonia converters die or never set up house in the media. So really the media is so poor it doesn't really matter how often it's cleaned.

Not trying to bum you out.

Thanks for the info waterbug_guy. The mesh mats do most of the filtering and the scrubbies on top probably do more bio. I suspect the activated carbon does nothing but I left it in there anyway (figured I'd take it out sometime this summer). There was quite a bit of muck in the mesh mats and that's where most of the earthworms were I think. Clearly there is plenty of O2 in the box since the worms were thriving. I think I better rinse the mats every 2-3 months.

There is indeed no harm leaving the activated carbon in there.

And no harm cleaning the mats whenever you like.

I get brown leeches in my filter media. They kind of look like worms too. I guess they are harmless.

I have the same biofilter setup. The water is pumped into the bottom of the container and then there is 2 layers of mesh mats and then 2 mesh bags above that filled with scrubbies. I also tried the activated carbon when my water got stained brown the first year after building the pond. I don't think the carbon did anything. The brown water was from the tannins in the blossoms of the ash tree which is above the pond and the tannins break down on their own after a month or so.

I've had the pond for 3 summers now. If the water flow seems to be lower, I clean out the biofilter by getting a bucket and gently washing all of the media with pond water. It usually takes months before I see a reduced water flow. When I clean, there is always gunk in all the media, especially the mesh mats. I've always had earthworms in the mats too, some several inches long. I'm sure they hate it when I clean the mats. I've wondered if it would be better to clean out the mats more regularly, especially in the hot summer months (Texas).