In another forum, I was reading how to get yellow stains off the return jets. It sounds as if the stains might have been caused by contaminated salt (iron) that I put in the pool--it was solarized salt 99.7% percent pure, or so the packaging said. One person said he has luck removing the stains by rubbing with Vitamin c in a sock and using metal out in the water. What does metal out do to an SWG system? He also said he lowered the SWG output and ph before he added the metal out. Why would he do this? The yellowing is quite unsightly. I would like to clean the jets up. Thanks, Dorie