Brown on walls by return jet.

[bean9677]

There is a large brownish area on the wall of my pool where the return jet is located. I have tried to brush it off, but it will not come off. Would anyone know what would cause that, see attached pictures.

FC-8, a bit high I turned the generator down this morning from 25% to 15%
CC- 0.5
PH- 7.5
TA- 70
CH- 450
CYA- 70
Salt- 3200

 

[Texas Splash]

Try rubbing a Vitamin C tablet on the stain. If it lifts it, it's iron.

 

[reggiehammond]

Are you on well water or ever had iron issues?

 

[bean9677]

Are you on well water or ever had iron issues?

I am not on well water and no iron issues in the past.

 

[Texas Splash]

Did you try the Vitamin C test yet?

 

[bean9677]

Did you try the Vitamin C test yet?

No sir, not yet. I have to get some.