Brown circle stains and wall stains


New member
Jul 1, 2012
We have a San Jaun pool and recently noticed that there are some new round stains on the floor and walls of the pool and advice would help. We don't use a well but with the 100' degree weather we have been adding alot of city water. We have a white fiberglass pool.


TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
Silver Spring, MD
Welcome to TFP!

Fiberglass stains even at fairly low levels of metals in the water. Try placing a vitamin C tablet on one of the stains. If the stain lifts around where the vitamin C tablet was then they are metal stains. If the stain is unaffected it might be something else entirely.