bk -
I feel your pain. I am in an extremely sandy area of southwest Kansas. My advice? Either find LOADS of clay to form an impervious layer or consider a liner.
We started out with a polyacrylamide/bentonite mixture and ended up with a dry hole. To top it off, the soil tech that sold us the product has avoided us after he guaranteed that the pond would seal. It didn't.
The ESS-13 product requires a MAXIMUM seep rate of (I believe) 8 inches per day otherwise I don't see it working. It's expensive, yes, and I would recommend it to someone that has a soil that ISN'T sandy like ours.
Search for a source of clay in your area. If you have a smaller pond you can also try buytarps.com they seem to have the best price for liners.
I wish the additive would have worked for us and maybe it would have if we didn't have such a shady technician. However, a seep rate of 13" a day doesn't sound like success to me LOL :rolleyes:
