I am a bheginner and I chose to use marble 12" X 4" x1" marble bricks, three tall, around my 8' X 6' asian water garden. It has two levels, 75% of it is 2' and the trest 1ft'. I used a 4" ledge around my pond for the level placement of the bricks and allowed for pea gravel and leveling sand, underlayment, and 45MM EPDM rubber lining. My problem came when trying to level the bricks. at the liner stage. I never got to the waterfall foam and liquid nails part, as I could not get these bricks level when I came to the numerous folds in the liner on the corners and walls of the pond. Any ideas how I can get this pond edge level? It was level when I tested it on the pea gravel and leveling sand.