I recently built a 190 gal pond in my garage using 4x4's stacked log cabin style. The outside dimensions are approximately 5.5' long x 2.5' wide 2.5' deep. I lined it on the inside with 1" styrofoam insulation and a piece of pond liner. I built a skippy type filter based on koiguys filter with a 20 gal brute garbage pail and a 500 gph pondmaster pump. Water quality is now excellent and the 13 3-5 inch koi, goldfish and shubunkins seem happy.
It was easy to build but a bit more expensive that I was expecting.
It was easy to build but a bit more expensive that I was expecting.