POND VEGGIE (PLANT FILTERS); The four basic types of veggie filters and how to install them.


Umbrella Plant

Plant or “Veggie Filters” are very popular with many pond keepers. I have been using this method for pond filtration for a few decades (long before the term veggie filter became popular). Veggie (plant) filters are excellent for removal of many nutrients that cause green or cloudy water (including nitrates, phosphates, etc.)
There are two basic methods (that I am aware of), the more popular method nowadays is a separate pond filter. This is not my preferred method, however both work very well (I will discuss each latter). Any plant with a good root structure that grows fast and has the majority of their leaves above water (basically a bog plant) is a good candidate to start with. I recommend water iris for their strong root structure, fast growth, great nutrient absorption, and a great place for baby fish (fry) to hide feed and grow.

I prefer my plant filters within the pond as these look more attractive in my opinion and give the fish fry a place to hide (except in the case of the waterfall or cascade plant filter).
The area of the veggie filter should be relatively shallow as well to force water movement over and through the roots
There are many other excellent plants as well such as Sweet Flag, Parrots feather, Bluebells, Umbrella palm, Papyrus, & bull rush. Make sure these types of plants (plants with roots in water and leaves above) are planted in an area of good, but not strong water movement. This ensures that they will do their job as plant filters.

I recommend starting your veggie filter plants in pots (I prefer ceramic or even the bio degradable type) as these will contain the plant roots in the beginning, yet allow growth of the roots out of the pots. I highly recommend using Volcanic Rock in the area around the pots to fill in the gaps and allow for additional filtration. The advantage of volcanic rock is that its porous structure allows formation of aerobic bacteria for nitrification and anaerobic bacteria for de-nitrification. This further enhances your veggie filters ability to keep a clear pond by removing the nutrients necessary for green water/algae. The volcanic rock is also an excellent growth substrate for the plant roots as your veggie filter grows.

If water movement is poor in the area of your Veggie Filter (plant roots), I would recommend a submersible pump placed near the veggie filter with its outflow aimed at the veggie filter. Make sure this current is not too strong, so angling the outflow if the current is causing too much disturbance of the roots, volcanic rock, etc. Another way to circulate water in the area of an in pond Veggie Filter is to add a fountain to your submersible pump so as to have a more gentle spray in the area of the plant/veggie filter. I generally use a pump with a flow around 500 -1000 gph around veggie filters in a pond of approximately 300- 1200 gallons (this may be increased or decreased depending on the pond size). The Via Aqua 2600 is an excellent pump for use here with a flow of 740 gph. Other suggestions include the Via Aqua 3300 or the ReSun King 3A.

Be patient with a veggie filter as unlike many other forms of pond filtration, a veggie filter takes a while to become effective (often a FULL growing season!). This is why it is a good idea to have additional filtration as well such as a Pressurized Pond Filter and a UV Sterilizer



VEGGIE FILTER METHODS:


Click picture to enlarge

[1] Corner;
Place your plants in a shallow corner of the pond with ½” -2” rock under the plants to allow the roots to better establish themselves, do not use sand or soil. The water depth is best if the roots are barely covered by water. Add a slow to moderate (200- 600 gph) separate water supply (a diversion from your main water pump or a separate pump) to these plants make sure the water passes through the plant roots, not just over them.
An air pump such as a ReSun 9603 or Million Air 600 can also be used and placed in the middle to draw water in via the rising air column.

[2] Constriction;
Similar to above, place your plants in a shallow corner of the pond with ½” -2” rock under the plants to allow the roots to better establish themselves, do not use sand or soil. The water depth is best if the roots are barely covered by water. In this case, allow the water to move from one pond to the other thru this constriction area in a manner that maximizes root exposure to the water flow (again, not high a flow)

[3] Waterfall;
In this method the plants are in the waterfall or cascade area of the pond. Again place your plants in a shallow corner of the pond with ½” -2” rock under the plants to allow the roots to better establish themselves, do not use sand or soil. The water depth is best if the roots are barely covered by water. This method can be combined with other methods. The downside to this method if used by itself is it does not give the fry a place to hide and often water flows and water depths are harder to control for maximum efficiency, however this method still works especially when used in combination.



[4] Separate Veggie Filter;
This is a more popular method lately, although my least favorite.
In this method you would use a container such as a tub or small pool and pump water into these “Plant Filers” then water flows back into the main pond. I have seen nicely set up separate veggie filters where they are actually constructed into the ground or into a terrace, these do look better than the tub methods (these are more similar to the waterfall method). My problem with this method is similar to the waterfall method in that flow around the roots and water level (just above the roots) is hard to control to maximize benefits of the plant root structure. You also loose the benefit of a place for fry or breeding adults to hide as in the first methods.
Here is a site with a little more about this type of veggie filter:
Plants, tips and tricks

CONCLUSION;
A Veggie or Plant Filter is an excellent compliment or even stand alone pond filter depending on the volume and filter (root) area and exposure of the plant filter.
A compliment to a simple Hydro Pond Filter is what I would recommend. The Hydro Pond IV can be connected to your Pump as a pre filter (these are rated up to a 1500 gallon pond), then a UV Sterilizer in line (best if used at slower flow rate) would further compliment this system. As for the pump, I recommend the ReSun King Pumps as they are a good combination of state of the art impellers (ceramic shaft, stainless steel sheath) and value.

FOR MY FULL POND ARTICLE, please visit this link:
“A CLEAR POND, PROPER POND FILTRATION, CLEANING & MORE (even pond scarecrows for predatory birds)”