Jared France

Thanks for your reply Bryan.  To clarify, I am not intending for the filtration to be perfect, just to reduce how often I have to clean out and empty the pond water, while producing some aquatic veggies for the ducks.  I will definitely be using the pond water for the garden and would have to top it off when I do.  I guess I am drawing more from things I have seen about duckponics, but substituting reeds instead of regular veggies for the gravel filter beds.  Some of them seem pretty darn simple and appear to work pretty well even without reeds.

Some examples I have found:
https://www.youtube.com/watch?v=qOWFvvYH2CU#action=share
https://www.youtube.com/watch?v=_o36aZHKZl0#action=share  (my favorite, extremely simple yet functional)

I plan to use a "swirl filter" like the one shown in the 2nd video to remove solids initially.  That video uses an old bathtub as a pond, which are generally about 50 gal, which he then filters via 2 kiddie pool gravel beds (probably 25 gal each).  The difference with my livestock tank is that there is much less surface area in relation to the volume of the container, so I assume kiddie pools would be even better filtration.  But I have these tanks, and kiddie pools always seem to disintegrate after a season or two.  It is always possible that I just use the entire tank to grow aquatic plants and then just add kiddie pools until i am satisfied with the results.

I forgot to add that this is just for 6 ducks at the time being.

I am looking into designing a duck pond filtration set up using two 300 gal livestock water tanks I came into possession of.  One would become the new pond (a nice upgrade from our kiddie pool), and the other would provide filtration.  I have been unable to find any duckponics or duck pond filtration designs that incorporate reed beds, oddly enough, although I am sure reeds would do the job even better.  I won't go into the details of the actual design, but I am hoping to section off up to half of the filter tank to be used to grow watercress and duckweed (which may provide some filtration) for duck food before flowing into the gravel-filled reed bed section, as long as I have enough reeds to do the final job.  My goal is to provide a good deal of aquatic plant food for the ducks, but keeping the pond water clean has to be the highest priority given how much time, energy, and water this will save.  Would half of the 300 gal tank provide enough space for a suitable reed bed filter or should I maximize the amount of space used for the reed beds?  I suppose I could always add another smaller tank (which I would have to procure) for growing aquatic plants and just use the entire 300 gal tank as a reed bed, but I'd rather keep it small and simple if at all possible.

Thanks in advance for your thoughts and ideas!

Eric Hanson wrote:

So I understand that comfrey has a really spectacular growth rate.  What I don't understand is where does it get all of its nitrogen?  I know that its leaves have a very high N rating, and not being a legume, cannot fix nitrogen from air.  As far as I know, that leaves the soil.  I would think that the soil would eventually run low on N, but many suggest otherwise.  So just how does comfrey get its N?  

Comfrey is a nutrient and mineral accumulator.  It can have taproots up to 20 ft deep.  So in poor soils it may be a little slow to get started as it puts it's roots in, but with some care should take off once established.  In rich, moist soils it seems to take off immediately.

I see it as a scavenger plant, soaking up nutrients that have soaked deeper into the soil than most plants can reach and recycling it back up to the soil surface.  This is why people use it to border garden beds or poultry runs, because it can help to slow runoff and recycle some of the lost nutrients.  Pretty incredible plant, and in no way limited to just a Nitrogen plant!  Also Phosphorous, Potassium, and a whole spectrum of minerals.

I would say that the best companions for comfrey would easily be the N-fixing shrubs or trees.  If you already have a use for alfalfa, that could totally work.  If not, choose something that has some use to you.  

Comfrey seems to get along nicely with anything taller than it that doesn't mind having it's roots shaded out (most plants/trees seem to enjoy this, but raspberries for example need more air circulation around their base so do not make good companions).  It quickly out-competes any other groundcover near it as it expands.  My entire yard has comfrey growing everywhere, just as a weed.  You seriously cannot kill it.  There are certain places where they have formed mass patches of maybe 50-100 plants, it's hard to say.  The only thing that manages to survive among them is the odd blackberry vine that escapes my attention until winter when the comfrey dies back.  

As mentioned before comfrey is very shade tolerant, so I would be more worried about the success of the companion rather than the comfrey itself.