'Rust' Spots in Pool

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Casscat
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Post by Casscat »

Just returning to this and hoping for more advice. The staining is no better, and if anything has become a little worse. The pictured patch is the larger of two.

Image

My property guy has tried the suggested treatments and has been down to the bottom of the pool with a snorkel and a scourer. The rusting does spoil then otherwise idyllic look of the pool and I'd be really grateful for further suggestions :(
RichardHenshall
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Post by RichardHenshall »

That looks to me like the rust is coming through the grouting and is probably the steel reinforcing bars from the concrete shell rusting.

I'm no expert but it might suggest a void in the concrete behind/beneath the tiles that should be properly repaired, with the pool drained.

An interim measure might be to use something like Tufmix 2-part epoxy putty to fill any cracks or missing tiles/grout. This can be applied underwater.
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kevsboredagain
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Post by kevsboredagain »

As Richard says, I assume it's this:
https://sites.google.com/a/solvemypoolp ... ebar-spots

Temporary cleaning tips include acid pellets in a sock placed on the stain to acid poured down a PVC tube to localise the cleaning. Repair would seem to be the only long term solution.
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Casscat
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Post by Casscat »

Worse than I thought then :( I was hoping it was topical staining which could be removed with the right solvent. I will pass your comments on to my property guy. Draining down the pool & refilling is going to be a nightmare as I am not on mains water. Obviously it will have to wait until the end of the current season as the bookings kick in from the end of this month. I'll get him to try your temporary cleaning tip Kev.
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CSE
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Post by CSE »

Draining down the pool & refilling is going to be a nightmare
Hate to bring you the bad news. If it is the rebars that is the least of your problems.
Personally I would be thinking leave it alone and see what happens.
Maybe and I would hope this is the case this si the only spot(s) you have. Then it is a pain but it is not worth doing anything about now.
If the spots multiply then there would be a case for taking further and more drastic action.
Never try to out-stubborn your guests.
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Casscat
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Post by Casscat »

There was a similar, smaller rust mark on the side of the pool, just above the waterline (might be slightly below in a fully topped up pool). I've just been out there with some Cif and a microfibre cloth and it's gone. If only I could get to the bottom of my pool with Cif and a sponge!
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teapot
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Post by teapot »

Hmm, annoying and watch your water level in case it's a crack. Adding a sequestrant will help bind the iron so it won't begin to deposit elsewhere, like your water line mark which is probably from the iron already in the water.

Using Cif or other surfactants is to b avoided as it flushes all manner of stuff out of the filter back into the pool. A vitamin C ascorbic acid tab applied to any iron stain will remove it from the surface without adding surfactant. The chlorine needs to be at or near zero to achieve this or more ascorbic will be used.

Vitamin C doesn't actually remove it, it just changes it's form into the soluble type of iron but it will return and deposit again.
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kevsboredagain
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Post by kevsboredagain »

Casscat wrote:There was a similar, smaller rust mark on the side of the pool, just above the waterline (might be slightly below in a fully topped up pool). I've just been out there with some Cif and a microfibre cloth and it's gone. If only I could get to the bottom of my pool with Cif and a sponge!
For tile repairs I get a concrete block, attach a rope and tie it somewhere outside the pool. I use the block to keep me under the water and then pull it up with the rope when done. I'm sure the professionals do it differently :lol:
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teapot
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Post by teapot »

I use my shot belt (scuba equipment) less likely to damage anything compared to a normal weight belt.
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Casscat
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Post by Casscat »

teapot wrote:Hmm, annoying and watch your water level in case it's a crack.
Water level is fine it would seem - holds reasonably well outside of the summer major evaporation season.

The amount of Cif I used would be hard to detect with a microscope so I don't think any harm was done. I'm just very concerned as to what the deeper problem might be. I really can't afford to rebuild my pool from the ground works up :cry:
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CSE
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Post by CSE »

A rebuild could be on the cards.... eventually.
The rusting of the rebars (reinforcement bars) is going to push out tiles and crack the cement under the tiles eventually. The metal bars will rust away and the support to the strength of the structure will be non existent.
Basically what you have not got is enough concrete cover.
http://en.wikipedia.org/wiki/Concrete_cover

This will explain what the reinforcement bars do, in simple terms.
https://www.youtube.com/watch?v=zW6uGjURuNo
Personally I thought the proposed method of placement of the mesh sloppy. In this video one can see spacer supports which ensure the mesh is located correctly.
https://www.youtube.com/watch?v=q9C8ibLSZBc - Those cup type things.
Maybe the guy in the first video done your pool hence the reason why the bars/mesh is now rusting.

There are ways of halting the corrosion. They way I have seen it done is using cathodic protection. But these were to public swimming pools. But at least this prolongs the life of the structure without a need to rebuild.
http://en.wikipedia.org/wiki/Cathodic_protection
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Casscat
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Post by Casscat »

Thanks for the cheering thoughts :( Less than 12 months in and I have a 10x5m pool to rebuild? The coffers are empty on that one.
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CSE
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Post by CSE »

Did write the possibilities; and who knows how long before it fails or looks very poor. The rest of the post was about an explanation of what is going on. Just so you know.
Seeing as it is new, have you got any sort of builders guarantee?
In the mean time....Just get diving with your belt on and clean the stains.
Never try to out-stubborn your guests.
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Casscat
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Post by Casscat »

The pool is not new, but my ownership of it is. I do appreciate all input no matter how depressing. I will send my aquatic property guy in with his scourer as I don't like getting water up my nose :mrgreen:
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teapot
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Post by teapot »

Casscat, can you post full water test results? That way we can get a picture of the water and if it's corrosive what corrective measures you could take.

Water hardness
Calcium hardness
Alkalinity
pH
Cyanuric acid
Chlorine
Salinity
Water temperature

Is this a salt/chlorine pool?

Probably as others have said at that point the rebar was too close to the surface or they skimped on the concrete.
Not quite as bad a picture as some paint, a small area of rusted rebar isn't likely to be a catastrophic failure.

Can you contact the Spanish water people, often the large water companies have temporary water storage bags/dams you could fill to save wasting the water when its time to carry out the work.
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