A sealer coat is a material applied to the top layer of a concrete or gunite swimming pool.
Since concrete and gunite are porous materials, they can allow water and chemicals from the pool to seep into the concrete, weakening it over time.
On the flip side, the sealer coat also prevents groundwater or soil contaminants from entering the pool.
There are a variety of different sealer coat materials you can use on a concrete or gunite pool, each providing its own durability and appearance characteristics.
Sealer coats are also applied in the form of a waterproof membrane over tile or other porous materials, which may cover the bottom of an inground pool.