Quote Originally Posted by rpoldervaart View Post
My light rings are fine after 6 years of salt pool. So I wonder if it needs air for the rust to form.
It has more to do with the quality of the material. High quality stainless steel is not usually a problem. However, some less expensive pools use inferior materials, most often with screws but sometimes with light rings. We've seen a small number of such reports for light rings and quite a few more with screws. As I noted earlier, this can all be mitigated through use of proper materials or when that is not possible (such as when using aluminum), then using a sacrificial anode. For stone, one can use harder stone or can seal it regularly. One can also wash off decks regularly to remove/dilute the salt (that's what rain does and is why some areas of the country don't have this problem even with softer stones).

The vast majority of SWCG do not see problems. However, as they get lower in price and are used on lower-end pools, such problems will increase unless manufacturers takes such trends into account and improve the quality of the materials used. Also note that even non-SWCG pools have the same corrosion and stone degradation issues -- they just take longer to occur due to the lower salt level.