I used a product manufactured by
Prinsco. Up by me, their product is distributed retail by Menards. My contractor just happened to have an account with Prinsco, so I used his account to purchase the product direct. I can't recall the savings, but I believe it was 20 - 30% off retail at Menards.
I used 6 sections of 18" diameter x 20'. My contractor (who has constructed many ponds) insisted that we use smooth core dual wall at each end. The idea is that our freezing climate can freeze water at the exposed ends. If these exposed ends are corrugated, they will collect water and freeze. If there is any crap (for whatever once-in-a-lifetime reason) laying in the same area, it might freeze and get stuck. Then, when another rush of water comes thru, the clogging potential raises exponentially. Everything in between is regular corrugated and much less likely to freeze. They are connected with plastic collars and the pipe is carefully packed with a jumping-jack compactor.
