Hi All,
Thanks for all of your input and sorry for this late response. I had to leave on a business trip and am responding from Austria.
Here's a little more info about what I am trying to do.....
- I've attached a drawing of the pond layout that I am looking to build
- The main pond is the large section in the middle
- The two "wings" are supposed to serve multiple purposes:
- Settlement Chamber (sloped from BD feed end down to pump/biofilter intake)
- Pre-/Mechanical Filter (perhaps using approx 1' from center around intake to pump/biofiltration to house layered Matala media (black, blue and grey) which I am hoping will provide good mechanical filtration and decent "initial" biological filtration
- Watergarden (a compromise, since my wife want "some" plants in the pond. I figured the plants could inhabit the top 8" to 12" of the settlement wings and provide additional nitrate filtration)
- I'm configured 2 4" bottom drains with aeration due to the length of the pond (26'). I didn't think that one BD would be sufficient, unless I had a steep grade from one end of the pond to the other. Since the main viewing area will be around the center, I wanted the "wells" to be there as well.
Each bottom drain would feed its own dedicated settlement "wing" (chamber)
I originally had the biofiltration chambers built into the pond (centered, 3' into the pond, behind a 5' high wall supporting falls). Under this option, the falls would have been gravity fed by wet/dry filtration towers. This layout looled good "on paper, but when I layed the design out in the yard, the filter wall took up too much pond space (proportionally), so I had to move the filtration "next to" the pond. This move also reduced the amount of available space that I had to allocate to the final filtration area.
Due to the reduction in final filtration real estate, I "thought" that the best way to get adequate filtration, and enough pressurized flow to feed the falls, would be to switch to a pressurized filter set up (a la Alpha1 or Polygeyser). The other option would be to gravity feed into 2 independent submerged biofiltration bins (perhaps filled with more Matala media (blue and grey) and pump feed the falls from there. I did not know if the latter would give me sufficient bio filtration capacity (each bio bin would be about 2'x3'x(18" or 2' deep), so I opted for the pressurized filter option. If my assumption is incorrect, please let me know, as I would prefer a gravity fed system for both flow efficiencies and maintenance reasons (as I assume that I would be able to push my maintenance (cleaning) schedule out to a semi-annual cycle as opposed to a weekly, or bi-weekly, backflush schedule.
Starting out (for the first 2 to 3 years) I doubt that I will be pushing my filtration system. I plan on starting small, a few 4" to 6" fish, growing them and adding to my collection as time goes by. Ultimately, I would like to have the pond stock grow to about 18 to 24 "good sized" koi. It is this "end state" that I would like to build my filtration capacity to handle, so I won't have to worry about replacing equipment and re-designing my systems a couple years down the road.
Once again, thanks for all of your help so far and any additional input that you can provide would be greatly appreciated.