The GrazenFilter Backstory

The GrazenFilter is really a story about rocks. I like rocks. The fish like rocks, too. Rocks give the pond a more natural look.

But, there’s a problem. Backyard ponds are a closed system; the same water circulates over and over, unlike a stream where water is constantly being replaced.  Rocks placed immediately atop the pond liner can harbor nasty, potentially toxic muck. That’s why so many pond experts advise against placing rocks on the pond bottom.

To workaround this muck problem, I raised the rocks off the liner with a flooring system made of PVC posts, aluminum lintels and plastic grating. This creates a false bottom where rocks can be placed. Water flows through these elevated rocks instead of stagnating between them.

Predators hate this system, btw. When bad guys grab a seat at the lunch counter, fish ain’t on the menu. They’ve escaped to the safety of the lower level. Problems solved, sort of.

A floor made from elevated rocks hides the unnatural components -- liners, pumps, pipes, pre-filters, etc. But, it really hampers access to the pre-filter, which already demands frequent attention.

Enter our heros, THE FISH. They glide effortlessly through these human-unfriendly spaces. And, they’re looking for work. In fact, they'll work for food!

The GrazenFilter, patented in the US and 12 other countries, makes it possiblew for fish to indulge their food foraging habits and take over my cleaning chores -- “Teaching a fish to fish”, so to speak.

They graze along the surface all day long on the top, sides and bottom. They take a bite and chew, swallow what they want, then spit out the rest in a cloud of tiny bits.

These masticated leftovers are small enough to pass through the screen and, of course, anything that can pass the screen can also pass easily through the pump. After the pump, typical biological filtering techniques are used to breakdown and/or collect the remaining debris.

If it’s too cold for the fish to work or there’s simply too much debris for them to handle, a backwash system opens free flowing space on the filter surface. It doesn’t take much, just a good blast from the internal water jets to loosen and open gaps in the screen.

It also serves as a convenient way to add water to the pond and it really stirs things up for the fish. When the backwash turns on, the fish come running and will soon dispatch any debris that’s still adhered to the filter screen.

The GrazenFilter allows for a symbiotic transaction between itself and the fish -- what’s known to economists as an optimal “voluntary exchange”. A "win-win”, in other words.  The fish are happy for an easy and frequent meal. I’m spared the filthy and frequent drudgery of pre-filter maintenance.

Pre-filter maintenance is no longer my job. My hardworking fish handle that task. They never gripe about it. In fact, they’re happy for the opportunity. And, when they can’t get the job done because it’s too cold or there’s a big load of junk that they can’t handle, I simply turn on the backwashing system.

There are a handful of GrazenFilters out in the wild now. But, I’m looking for a few more testers. If you’re interested, please complete this form.

Or, if you’re in the pond industry and looking for a way to differentiate your products from the competition, please contact me. I’m open to any patent licensing opportunties.


We are looking for licensing partners and field testers. Enter your information to get more details.

For field testers, please provide as many details about your pond setup as possible – size, pump location, pump specifications, etc.. The more information the better.

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