That's exactly what I did pool-newb. I was trying to avoid that because I read in a post on here that they are all "trying to sell you something". And another link that took me to Pool School offered no remedy for it either. It says to consider having enough water trucked in to fill it. It was absolutely no help at all.
We put the pool up last Friday. I treated it just as I did our other pool before we moved and had to use well water. I shocked it and added sanitizer tablets. I didn't realize there was that big of a difference in well water and county water. I found out quickly when I added the shock treatment that the difference is huge!
By Monday I was fed up. We had a brand new pool that looked old, stained, and worn out. I wasn't getting any replies to my questions, so I finally called a local pool supply service. I am so glad I did. I took in a water sample from the pool. She checked it and found that there were very high concentrates of copper and iron in the water. The pH was also extremely low. The chlorine wasn't right either. Here is what she told me to do:
Monday evening, I added 17 oz of Metal Magic and used a new filter.
By Tuesday, the water was crystal clear again. I did have to agitate the water a bit so the rust could float around and it was filtered out rather quickly.
I changed the filter again Tuesday morning.
Tuesday evening, I added two sanitizer tablets. The water stayed clear.
Approximately 3 hours later, I added a one pound shock treatment and a four pound box of Alkelinity Plus. The water was still clear.
The kids were swimming in it today. The water is clear. All the rust stains are gone. I'm glad I finally made the call.