Red/copper Stain

duraleigh

Admin
Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
34,430
Sebring, Florida
I agree with JamesW. It looks like iron and viamin C (crush up several and put them in a sock and then directly onto the stain) will remove or minimize it.
 

setsailsoon

Gold Supporter
LifeTime Supporter
TFP Guide
Oct 25, 2015
3,485
Stuart/FL
How do you disinfect your pool? Have you used any kind of algae or mineral treatments? Please fill in your signature. It will help you get faster response from our experts and help them be more efficient with their volunteer time. Here's how.

Chris
 

JamesW

TFP Expert
Mar 2, 2011
21,092
It might be iron embedded in the plaster and bleeding through.

Try putting a strong magnet on the bigger spot to see if there is any attraction.