Place the Stones
Place the stones. Placing stone in the pond serves many purposes: stone keeps the liner in place, protects it from ultraviolet rays and makes the pond appear natural. Stone also creates a surface for algae and microorganisms to colonize on.
To determine the total tonnage of boulders, larger stones, needed for your pond, take the length times the width of the pond and divide it by 65. A quarter of that tonnage should be small stones, a quarter should be large stones and half should be medium-sized stones. To figure out the amount of smooth gravel used for filler and for covering the liner, take the boulder tonnage number and multiply it by .45.