Hi Janet,

It is a vinyl lined pool.

How do I know if I have copper, etc? The water in our area has a lot of iron in it - it has been a problem in the past, as in when we add water it comes from the hose into the pool yellow/brown and turns the entire pool a greenish yellow. It has been helped a lot by adding water via putting the hose in the skimmer and having it go through the filter first. It would be a good guess that we have metal content in the pool, especially since I have added water several times with the garden hose, due to vacuuming to waste and lowering the water level.