Sorry I can't find a pic of lsst pond to check (hint: add a link to it in your post helps!) but in general a veggie filter is just a bunch of plants that share the same water with your pond.

The basic bacteria bio cycle is fish pee - > ammonia -> nitrites -> nitrates. The nitrates are mildly toxic but build up to unacceptable levels unless you do water changes OR filter them out too. Now nitrates are God's own plant food. So just add plants to close the cycle and keep the fish safe. Also, plants that eat nitrates leave nothing for algae to eat so helps clears your green water too.

Koi love to eat plants so sometimes you can't add them directly to your pond. So in some ponds there is a plant bog or some feature so water from the filter runs first to a pool that has no fish, then falls to a pond where the fish live. A netted off area works too.

I have a little pond (180 gallons) with just a few goldfish and one or two small Koi (12 & 15 inches). I cover my water with floating plants, water lettuce & hyacinths. They will grow quickly enough so the fish have plenty to snack on, in fact they will cover the whole surface if I don't pull some regularly to stock my compost bin.

Yes, I use a little UV filter too but even without it I've had gin clear water, just with the UV I can have less plants, crystal water, and lots of open water to see fish!

BTW, my fish seem to love the plants as they live for the most part under their cover, except when I bang the side with their fish food can, then they come RUNNING out to the open area where I feed them.

A veggie filter is sometimes called a bog filter. A veggie filter can be any kind of container, from a small pond adjacent to the main pond, to a rubbermaid tub. It is a container intended for growing aquatic plants. The pump pushes the water into the container, and the plants absorb the nutrients in the water and the gravel grows the good bacteria.

I have 3 veggie filters. I have one in a pond with 19 inch koi. We make our own filters with a pump in a plastic box with holes drilled in it, and bio balls, and batting. The pump then pumps water to a tub with plants in it. The plants I use are water iris and water celery. They are bare root and I also put taro and a swamp mallow plant in it too but they are in pots. The bare roots filter the water and it spouts out into the pond.

here is one from a few years ago
[IMG]http://i53.photobucket.com/albums/g69/PHPong/100_0940.jpg[/IMG]

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My veggie filter is basically a 300 gallon stock tank.

I have a bottom drain gravity feeding into 55 gallon barrels.

My external pump takes the water from the barrels to the stock tank.

In the stock tank I have a grid of two inch pvc pipe with numerous holes drilled in them so that water disperses all into the stock tank. I have planted numerous cat tail, iris and other plants in the tank.

I made a weir out of stainless steel angle iron and attached a flat stone on top to make it look more natural.
I did use stone on the sides and driftwood to cover the sides of the tank.

I have a drain in the stock tank so that it can be drained in order for me to cut back the plants when necessary.

Here is a pic.The stock tank is on the left. I have a regular bio falls on the right.Both are inside the pond as the back is a 40 inch wall.

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Here is a pic of mine from last year.

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Breathtaking ponds and plants. Since I don't have koi, I guess I don't need to separate the plants. Thank you for the photos and information.
Vickie, your lotuses are amazing.

Renee