If there are no steel pipes used in the pool construction then the iron was present in the water before it was added to the pool.
i need to know how to get rid of green water
Iron salt? I assume you are talking about iron the mineral. The method to get rid of iron depends on several different things. First the type of sanitizer you are using and how high the iron level is. So if you can send another question with the that information and how many gallons of water you have in the pool I can answer your question in better detail.
The water can be drained outwith a hose.
Use a pool vacuum or get a bucket
Use a sequestering agent for Iron removal. k
pump it out
How can I get rid of rust colored stains in my salt water pool. It is only in the shallow end?
Empty the pool out and fill it with soil. OR Use chlorine.
u just clean the pool or buy a new one