Intractable Rust Stains

[DallasSocFan]

So I had a second floor put on my house.

Long story short, I've got a pox of rust stains on the bottom of my pool from all kinds of nails and hardware sitting there for an extended period of time.

I've tried vitamin C pills directly on them. I've even filled a pair of panty hose with 100% Citric acid placed directly on the spots. I've elbow greased right on them with pumice and steel brushes.

Nothing. The stains literally laughed. It was hard to hear since the laughs were underwater, but I heard them nonetheless.

Is there any other tricks I can go with?

**My GC was a close personal friend. He feels terrible about it, but although I'd be in the right asking for extreme measures, I won't. His subcontractors F'ed it up and ran off on him. He's slowly making it up to me with minor projects here and there, but asking for a replaster isn't something I'm willing to do.

 

[Texas Splash]

Odd, they look like iron but no impact from Vitamin C or citric acid? Just for peace of mind, can you post a full set of water test results? You are 100% it's from debris as a result from the contractor work? Nothing locally couldn't blown in from a storm or something?

There's only two other at-home tests you can try with common products:
- Rub some dry acid on the stains to see if there are any copper elements to them.
- To see if they are organic, you can try rubbing a chlorine tab on them. If it's metal the chlorine should make the stains darker.

So if none of that works, you may need to try Jack's Magic Stain ID Kit.

 

[DallasSocFan]

I pulled the nails out myself and saw the stains underneath them. Is it possible the rust is just too deep in the plaster?

 

[DallasSocFan]

About the test, I'm in the middle of a SLAM. Just prepping for when I'm on the other side.

 

[Texas Splash]

Is it possible the rust is just too deep in the plaster?

Difficult to imagine unless the plaster is old and the iron penetrated more than usual. Just a thought. Since you removed those nails yourself, iron would certainly seem like the culprit. @JamesW are there any other chemical possibilities we might have overlooked?

 

[DallasSocFan]

Difficult to imagine unless the plaster is old and the iron penetrated more than usual. Just a thought. Since you removed those nails yourself, iron would certainly seem like the culprit. @JamesW are there any other chemical possibilities we might have overlooked?

Is 10 years old for plaster? The nails were down there well over a month.

 

[Texas Splash]

Is 10 years old for plaster? The nails were down there well over a month.

Not for plaster that is well maintained. But for nails to be down there that long could certainly require more aggressive treatment. Let's see what James has to say.