| Are you planning a rectangular pond? If so you'll run out of liner with the dimensions you posted. The corners will use up another 2 feet each. If you go oval with a well rounded bottom at 5 feet max depth you "might" get away with the liner you have. If so, you'll get more like 128 sf of surface area (figure a 10 foot circle + 5 x 10 in the middle) x 4 ft avg depth = 3850 gallons at best. Liner is cheap...you can use the smaller piece as underlayment on the edges...
We cast our own retro bottom drain, using concrete in a plastic koi tub. Use pipe caps for feet, set for a 1/2" gap all around. We cast in two 2" pipes, low and to the side (we have a roll of 2" PVC flex already), and also an air line pipe & elbow for a 9" disc diffuser on top. This really helps the drain's efficiency, as the rising column of air and water "sucks" the waste along the bottom and into the drain. It weighs 50 lb, I don't think any fish are getting under it. The plastic drains need rocks or something for weight - ewww.
Good luck, Tom |