For whatever it's worth I was told by a very wise man...Do It Right the FIRST Time and I've found that advice to be true to this day. I've probably still have bruises to show for that. LOL...but I suggest doing it right..not hoping it seals and after you get it stocked to find out it wasn't and something comes loose 2yrs from now when you have a pond in good shape and have to drain. Just my thoughts