Hi
I've used fiberglass tarps in an aboveground ,since 1981.
Have had no problems with it but after the freeze of 07
it wiped out the entire population of tropical fish. Since I had to clean it out anyway I added another liner.
You guessed it another fiberglass tarp.lol My only objection is that I couldn't find the tarp in black so settled for a silver color.
i also used this on the "marsh garden" has been running since 98 . no problems. gary

Hey Pop Tart! Also, I'd suggest checking craig's list for used roof epdm. I've gotten used epdm for my last two pond expansions....one from the Minneapolis/St Paul area and the other from the Duluth, MN area for super, super cheap! I just got the last one for $75 for a 20'x18' piece.

Check out the post about roof epdm versus pond epdm on this formum if you have questions about using it. I can say that I've used roofing epdm twice now with no adverse effects on my koi. If anything they are healthier and bigger because they have more room to move around nowadays!

I am too going to make my pond most of the people think the tarps are a great and cheap way of making a pond, i recently purchased on of 20x20 for 20 dollars online and it seems great. Good luck