If you’re looking for a simple answer, the answer is yes. Saltwater chlorinators are perfectly safe for gunite pools. The biggest issues reported when using saltwater chlorinators with gunite pools have to do with the tendency of the plaster to stain over time when coming into contact with salt. This is, however, an issue with two simple solutions. As far as concerns about the gunite surfacing experiencing corrosion or pitting because of the salt in the water, rest assured salt is no more damaging to the structure of concrete than chlorine. Provided maintenance of your chlorinator and surfacing of your pool is kept at normal, expected levels, there’s no reason your saltwater chlorinated pool won’t continue to outshine the regular pools in the Oyster Bay, NY area.
What causes staining?
Pure sodium chloride (salt) is white, but colorless when dissolved in water. Some powdery white residue can be expected when draining a saltwater pool, but this is simply salt left over after the water has evaporated, and can be easily rinsed off. The trouble is that salt is very seldom pure, containing trace elements of the metals iron, manganese and copper. Iron creates a reddish, rusty stain, manganese a black/brown stain and copper a blue/green tint. Before you blame your salt chlorinator, these elements can also exist in corroding pipes of old plumbing and water conduit systems or simply be in a higher concentration in your area’s water supply. Staining may also be blamed on external factors such as leaves with high tannin levels that fall into your pool and color the water. Once you have ruled out the other possibilities however, there are two things you can do to prevent further staining.
Change your salt
As mentioned, a pure salt will not cause staining. Therefore, it’s worthwhile to invest in high-grade salt that is specifically formulated for use in pools. Pure sodium chloride forms a perfectly cube-shaped crystal because of the regular, repetitive shape of the tightly packed molecules. You can therefore judge a salt’s purity by how cubelike the grains are. As a general rule of thumb, the more irregular the grains, the more impurities it contains and the more likely it is that the salt will contain pool-staining metals. To further limit staining, salt should not be left undissolved on the floor of a pool. This can be reduced by adding small regular doses of salt to your pool rather than large infrequent doses.
RELATED: CREATING A BEACH ENTRANCE FOR YOUR SALT WATER POOL
Change the finish on your pool
As a more radical solution you could always change the finish of your gunite pool, opting for a tile or mosaic surface rather than plaster or exposed aggregate. This is more practical as a preventative measure when deciding on the design for your pool, but older gunite pools can be redone. Plaster and exposed aggregate present a fairly coarse surface that tends to be difficult to clean when staining occurs. Tile is less prone to staining as it presents a smoother, easier to clean surface that is less reactive to both salt and chlorine. With a mosaic or colored tile finish, the noticeability of staining is further reduced, becoming obscured by the pattern and color of the tiles.