Ah, ok, thanks for the informationI got my liner from Bend Tarp and liner in oregon. Back when I got it the liner was called ppl36. I was told no need for any underlayment, but I did it anyway, we are rocks with a bit of dirt.
The most versatile liner on the market being fish & plant safe, with high puncture resistance, AquaArmor is the strongest, most UV resistant pond liner in the industry.www.btlliners.com
It is one huge liner that is my bog and pond. We installed it on a nice hot summer day, with the warmth it was easy to lay out. Flexible enough I could do bends, cover a small shelf. The corners were not that bad, but there are wrinkles here and there over time they just look like normal bumps in land.
it is stiff, but I would never go back to epdm, for a big pond, I do have some epdm in my small deck pond, that stuff is so slick and tears easier than my big pond liner.
have a fab weekend