DIY Series: How to Build an indoor koi pond

The following instructions are how to build a 500 gallon indoor pond using lumber and pond rubber. With the proper maintenance and filtration shown in the picture this pond is capable of holding around 50 koi in the 9-12" size range.
Materials
Qty Description
12 2x8x6' Construction grade lumber
4 6' Deck Boards
2 4x8x1/2 Plywood
12 10x10 45 mil EPDM pond rubber
1 Box of 3" screws
1 Box of 1" screws

Assembly
  1. Pre-drill 4 hole at each end of 6 of the 2x8 boards.
  2. Attach 4 of the boards together with screws to form a rectangluar ring.
  3. Repeat the process with the rest of the boards. You should end up with 3 rectangular rings.
  4. Stack the rings on top of each other, until you have a rectangular frame 3 boards high.
  5. Cut the plywood and attache it to the inside of each of the 4 walls.
  6. Make sure you use plenty of screws. I recommend 3 rows of screws into each board vertically, and spaced every 12" horizontally.
  7. This step is optional. If you intend to use a gravity feed settling chamber, drill a hole through the boards where you intend to place the chamber.
  8. This step is optional. At this point, you could line the inside of the enclosure with foam carpet padding.
  9. Unfold the pond liner, and center it inside the wood frame.
  10. The method of folding the corners will be a hidden hospital corner. The first step is to fold the liner like so:
  11. Then fold the liner over to the other wall, forming a 45 degree fold at the bottom.
  12. Bring the fold up to the top edge of the wall
  13. Adjust the fold in the liner so that it meets up exactly in the corner.
  14. Repeat the process for the other 3 corners.
  15. Fill the pond with water. Keep tension on the rubber as you do this so that the liner fits tightly in the frame.
  16. Attach the pond ruber to the top of the frame with roofing nails or screws.
  17. This step is options. Lay a thick bead of silicone sealant on the top of the frame. The silicone will keep water from splashing through the liner dripping down the back of the wood frame.
  18. Cut the ends of the deck boards at 45 degree angles, and mount them to the top of the frame. Make sure the screws are centered through the board.
  19. For instructions on how to build the settling chamber for this pond go here.
  20. For instructions on how to build the filter for this pond go here.
  21. For instructions on how to connect a bottom drain to this pond go here.
My daughter loves feeding the koi!
My daughter loves feeding the koi!
My daughter loves feeding the koi!