i did speak with the ees13 folks from seepage control.com. nice folks. he was pretty upfront with me and said it would be pretty expensive for my pond! my pond is almost 4 acres, but 25 feet deep in ssome areas. so, i believe he said they have to calculate an amount for the volume of water, not just acreage. they were pleasant however. i'm glad i waited, because with a year of waiting, my pond is holding like a bucket of water (took time to saturate/pack whatever). i would comment that it does seem to be more convenient, cheaper, and better to try to seal when you are building the pond if you are concerned about it holding (i..e poor soil type) rather than "hoping" and trying to fix it later from what i've seen folks say on this site! mark
