Installing pool cove around the bottom, inside circumference of your pool wall before replacing your pool liner will help prevent excessive stretching and premature wearing, adding years to the life of your new liner. Why density matters in pool cove: Water pressure on the cove is directly proportional to the depth of the water. The deeper the water, the more pressure on the cove. The higher the density, the lower the amount of air in the cove. Air will compress over time, resin won’t. If the cove flattens over time, the liner will become stressed and possibly even pull on the wall structure. Available in 4 foot sections.