Unfortunatley, it was a monetary convience. Digging even a small pond, then lining it, and all the potential bad things that could happen cuz I have no idea what Im doing made a preform a logical answer for me. I will deal with getting it right, it gives me something to do. Worse case scenerio! The preform fails and I have a lovely fitted hole for a liner already there, right? (I hope?) lol.