Rust Spot on pool wall

[ngc4900]

Hi,

I posted this elsewhere last month with no response. The first one described below has not returned after the Pool Tech applied acid and used a pumice stone.

It has happeded again. I am not sure the cause or what to do?

Hello,

I have new 3 month old pool with a pebble Tech plaster wall. About 3 weeks ago I noticed a small brown spot about the size of a pencil eraser on the pool wall one foot below the water line. It looked liked like rust oxidation. Moving my finger over the spot did not reveal any hole or depression. I used a nylon brush to wipe over the spot and it appeared to fade a little. Over the course of time it darkened in color and slightly increased in size. I called my Pool installation company and they stated there was probably a small fleck of metal embedded in the plaster. He used a 1” PVC pipe about 2 feet long and poured Muriatic acid into the tube and placed it over the spot. He also used a pumice stone over the spot. It’s gone now but he stated if it returns, he will have to lower the pool water below the spot and fix it definitively. Has anyone ever seen this?

Honestly, I think pouring acid into a tube to affect a spot under the waterline is folly, but what do I know. Also, he used enough acid to lower my pH to 7.0

 

[reggiehammond]

Can you post some photos of the area?

 

[ngc4900]

I have to find a camera I can use underwater.

Can you post some photos of the area?

 

[reggiehammond]

iPhone 7 and up are waterproof, but you can also likely get a "good enough" picture from in the pool, looking down at an angle from outside the water.

 

[ngc4900]

 

[reggiehammond]

Crush up some vitamin C tablets into a sock or skimmer sock and hold over the spot. The Vit C will break down the rust and remove and you might be able to see the source a bit better. Any photos of the pool build in that area? A piece of rebar sticking through in that area?

 

[ngc4900]

Thanks I will give that a try. No areas of irregularity where I can detect something nightmarish like rebar poking through the surface wall!

 

[ngc4900]

I may get on of these:

Purity Pool Out Spot

 

[reggiehammond]

Acid removes plaster and causes roughness. Not something you want to be doing with any regularity.
If successful at removing the stain, you may end up with something with uneven finish or color, which is it's own special type of eyesore.

Stains in Your Pool

The stained pool is beyond embarrassing. Our in-depth Guide to remove stains in your pool will help you to remove the stains and prevent them in the future.

www.troublefreepool.com

There's also a few great wiki articles (available in left hand menu of site.)

 

[ajw22]

You have rusting rebar under the surface and the rust finding it way up to the plaster.

You can clear it with acid and pumice stone and after a while the rust will come back out.

Only long term fix is to expose the rusting area, cut it out, fill the hole with hydraulic cement, and replaster.

 

[ngc4900]

I was hoping this was NOT the case. The first spot has NOT returned. The pool is only 4 MONTHS OLD and still under warranty....... Is this common for NEW POOLS?

T&D POOLS, builds all the NEW pools for new construction homes in The Villages, FL, for the last 40 years - they have a stellar reputation here. I guess I am going to have to ask around and find out if others have had this problem.

You have rusting rebar under the surface and the rust finding it way up to the plaster.

You can clear it with acid and pumice stone and after a while the rust will come back out.

Only long term fix is to expose the rusting area, cut it out, fill the hole with hydraulic cement, and replaster.

 

[ajw22]

It is not common in new pools but if your rebar was not encapsulated with at least 3 inches thick of gunite/shotcrete then it can be a problem.

It really does not matter if other people had the problem. Sometimes the crew has a bad day and maybe it was at your pool.

Let the builder know, keep pictures and documentation of each stain, and see how it develops.

 

[ngc4900]

Great Advice! Thanks so much Allen. Your right. I need to have them fix it now before the Warranty period expires.

 

[ajw22]

What is the warranty period?

They should extend your warranty based on these problems showing.

 

[ngc4900]

I will check the actual warranty and your suggestion is an excellent one..... Thanks so much!!!

 

[ngc4900]

I think I may have found a potential source of my problem. This was found at the bottom of my auto-filler which is next to my skimmer.
It is a rusty nail actively oxidizing and dripping rust particles into the water.

 

[reggiehammond]

Was this right above the spot of rust in shell? I'm confused how this could be related

 

[ngc4900]

I just had the head (twenty-five years experience) of repairs/remodeling for T&D pools who installed my pool come over and look at the rust stains. He has fixed pools with rusting rebar issues over the years. He stated that rebar rusting through the plaster surface would go from the size of a pencil eraser to the size of a half dollar in a matter of a few days. He told me my spots, which have been there for several days and have not changed in size would have deteriorated in a massive manner over that time period. That is basically his argument why my problem is not a rebar problem.

We just installed two large outdoor automatic shades on the birdcage encircling the pool which involved drilling holes and leaving metal filings on the ground near the pool. His theory is that one or two of those metal shavings entered the pool and caused the spots.

I don't know. I have documented the spots and reported it to my my pool company. I guess I have to wait and see if this gets worst and then go from there. Oh, and pray if it does get worse it does so prior to any warranty issues.

 

[ngc4900]

Was this right above the spot of rust in shell? I'm confused how this could be related

It was on the bottom of the auto filler cell which sits next to my skimmer.

 

[reggiehammond]

We just installed two large outdoor automatic shades on the birdcage encircling the pool which involved drilling holes and leaving metal filings on the ground near the pool. His theory is that one or two of those metal shavings entered the pool and caused the spots.

What metal is the shade structure made of? How I think his excuses are pretty stupid, but I guess it's not completely impossible that a shaving large enough to cause that much rust could magically stick itself to the side wall of a pool.

But - I don't think that really passes the sniff test. Just be careful - these guys are likely experts in stringing you along, for long enough, to either wear you out to give up, or escape the warranty period.