Brown Rust-like Stain on Wall

[sharper4]

I had a new pool put in late last summer. We've been loving it. Over the winter I have kept the pool open and maintained it just like I do during the summer (all-be-it less chemical monitoring).

I have noticed a small rust-looking spot near one of the lights, on the wall (up and down, not where it rounds off to the bottom). It looks like a penny laid on the area and rusted and left a little streak ... but because its on the wall I know nothing simply fell there and stayed too long. I've been really good about getting out every couple weeks to continue brushing the pool. The cleaner still runs every week to clean anything off the bottom of the pool.

Here's the general location:

And here is a closer pic looking down at it (its located just about 3 ft down from the water line):

I have tried to scrub it off but it doesn't budge even a little. I can't exactly climb in and clean it by hand because a) I wouldn't know how to clean it and b) the water is so super cold right now (40+ degrees).

Any ideas of what it is or how one might go about cleaning it? Is this a possible defect that I should have the builder look in to?

Thank you much in advance.

 

[JohnT]

It's probably either a stone that got in the plaster or a piece of rebar that didn't get covered. Really doesn't look dark enough to be rebar.

Try rubbing it with a Vitamin C tablet to see if it lightens.

 

[sharper4]

It's probably either a stone that got in the plaster or a piece of rebar that didn't get covered. Really doesn't look dark enough to be rebar.

Try rubbing it with a Vitamin C tablet to see if it lightens.

How does one go about rubbing it with vitamin C? Afix it to PVC or the brush or something? What is a vitamin C tablet anyhow? Would I find that at the pool store?

 

[JohnT]

How does one go about rubbing it with vitamin C? Afix it to PVC or the brush or something? What is a vitamin C tablet anyhow? Would I find that at the pool store?

Just a plain old Vitamin C tablet from the drug store. It's a mild acid that will remove some metal staining. It's hard to tell how deep it is because your water is so clear I can reach my light laying down on the pool deck, but you may not be able to reach the spot.

 

[sharper4]

Just a plain old Vitamin C tablet from the drug store. It's a mild acid that will remove some metal staining. It's hard to tell how deep it is because your water is so clear I can reach my light laying down on the pool deck, but you may not be able to reach the spot.

Thank you John.

 

[sharper4]

Hello - I'd like to re-open this question. I put about 5 or 6 1000mg vitamin c tablets into a thin sock and held it on the stain for about 5 mins and it didn't discolor from what I could judge. What does that mean?

 

[Butterfly]

Just to be sure, you could crush the Vitamin C tabs in the sock and repeat the procedure. Some Vitamin C tabs have been coated and take a little longer to dissolve/show a result. Crushing should take care of that.

 

[sharper4]

I wanted to come back out here to share with the forum the outcome of this. It turns out that it is part of one of the metal twist ties that was used on the rebar. Apparently its sticking out from the concrete but not the plaster... but its close enough to the surface that it has shown this rust-like stain. The pool company is coming out to drain the pool this week so that they can repair the area. They will also refill with water and start the chemicals for us again. Stinks... but I'm glad to have it taken care of now rather than once the swimming season had begun.