yellow stain

Over the past couple of months, yellowish stains have been popping up and they are increasing and getting darker. They don't scrub off. I've been told a few things: 1. Possible rebar rusting. I don't think this is the case. The pool is less than 1 year old. 2. Salt creates stains faster...

I recently bought a house with a pool (first time pool owner). The edge of the pool seems to have staining that won't come up. I have tried brushing and and scrubbing it. It is only discolored on the ledge (The flat part around the pool where you can stand up no matter the depth). Does anyone...