Rusting Walls After 1.5 years? Normal?

JamesW

TFP Expert
Mar 2, 2011
22,101
Not exactly sure what you can do to prevent further corrosion.

Some ideas: Coat with a good rust proofing paint. Make sure that you have good drainage. Check for any stray current and address as needed. Maybe try to add zinc anodes to the bond wire to absorb some of the corrosion.
 

91stealthes

Member
Apr 23, 2019
22
Long Island, NY
Thank you.

I plan to scratch off the rust and paint it.

No issue with drainage currently.

I'll check for stray current when I get water back in the pool.

I have always had a zinc anode attached to the bond wire.
 

JoyfulNoise

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Those pictures indicate "white rusting" to me - the galvanized zinc coating is exposed to fresh water too often and zinc hydroxide (white rust) forms. You can often see this on motor casings that are zinc coated. You live on Long Island (I am a former resident of LI) - the soil is, for all intents and purposes, highly compacted beach sand. It rains a lot there and your aquifer is, in some places, less than 50ft from the surface. Rain water penetrates the ground and builds up in the sand layer sitting stagnant until it slowly absorbs into the aquifer. White rust forms in wet environments when neutral pH water with relatively little carbonate alkalinity is present.

The proper way to install a galvanized steel structure like those panels is for them to be coated with a chromate or phosphate conversion coating on top of the galvanizing zinc layer. The conversion coating slowly dissolves away but, in that period of time, it allows the fresh zinc galvanizing layer to develop a hard zinc oxide surface layer as opposed to a zinc hydroxide layer. I doubt Latham goes to such troubles because they clearly engineer "failure" into their products.

Sacrificial anodes are unlikely to help much. But if you wanted to try it, call up a marina and ask somewhere there if they know a person that does boat repairs. Magnesium anodes are bolted onto metallic boating structures all the time to prevent seawater corrosion.

All you can realistically do at this point is to clean off all the corrosion (white and red rust) with a stiff wire brush and then paint that interior surface with a high quality epoxy/zinc paint or, lower quality Rustoleum.

The panels are compromised, there's no way to fix it without ripping out the entire pool. Live with it and expect to get about 10 years or so before you'll need to do major repairs.

Sorry, it sucks, but this kind of stuff happens with steel walls. Many people go with polymer walls to avoid these kinds of issues.
 
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91stealthes

Member
Apr 23, 2019
22
Long Island, NY
Those pictures indicate "white rusting" to me - the galvanized zinc coating is exposed to fresh water too often and zinc hydroxide (white rust) forms. You can often see this on motor casings that are zinc coated. You live on Long Island (I am a former resident of LI) - the soil is, for all intents and purposes, highly compacted beach sand. It rains a lot there and your aquifer is, in some places, less than 50ft from the surface. Rain water penetrates the ground and builds up in the sand layer sitting stagnant until it slowly absorbs into the aquifer. White rust forms in wet environments when neutral pH water with relatively little carbonate alkalinity is present.

The proper way to install a galvanized steel structure like those panels is for them to be coated with a chromate or phosphate conversion coating on top of the galvanizing zinc layer. The conversion coating slowly dissolves away but, in that period of time, it allows the fresh zinc galvanizing layer to develop a hard zinc oxide surface layer as opposed to a zinc hydroxide layer. I doubt Latham goes to such troubles because they clearly engineer "failure" into their products.

Sacrificial anodes are unlikely to help much. But if you wanted to try it, call up a marina and ask somewhere there if they know a person that does boat repairs. Magnesium anodes are bolted onto metallic boating structures all the time to prevent seawater corrosion.

All you can realistically do at this point is to clean off all the corrosion (white and red rust) with a stiff wire brush and then paint that interior surface with a high quality epoxy/zinc paint or, lower quality Rustoleum.

The panels are compromised, there's no way to fix it without ripping out the entire pool. Live with it and expect to get about 10 years or so before you'll need to do major repairs.

Sorry, it sucks, but this kind of stuff happens with steel walls. Many people go with polymer walls to avoid these kinds of issues.

Thank you. Where do you see white rust; the installation photos?

In regards to Zinc Epoxy paint. Would Zinc Clad II or Zinc Clad V from Sherwin Williams be a good solution? Any recommendation on which or any other product?
 

JamesW

TFP Expert
Mar 2, 2011
22,101
Sacrificial anodes are unlikely to help much. But if you wanted to try it, call up a marina and ask somewhere there if they know a person that does boat repairs. Magnesium anodes are bolted onto metallic boating structures all the time to prevent seawater corrosion.
Do you know anything about powered anodes?

I wonder if applying power could help protect the walls?

Since it’s a pool, the design would have to be safe and not present a risk.

Maybe a battery in series in the bond wire between the wall and the anode to help increase the voltage pushing electrons towards the walls?


This is used on water heaters. So, I would suspect that it's safe. Maybe contact the company to see if it would work for your application.

It looks like the Corroprotec is 24 volts dc, but I suspect that any voltage between 1 and 24 volts dc would be sufficient to help protect the walls.
 
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JamesW

TFP Expert
Mar 2, 2011
22,101

Here is the basic idea. You use a battery or a rectifier and you increase the voltage between the anode and the cathode such that it provides better protection than the natural voltage generated between the anode and the cathode.

You could get a big block of zinc or magnesium and bury it in the ground where it can corrode. Ideally, the ground would be exposed to water. Then you connect the anode to the positive terminal of a low voltage dc power supply and the negative terminal goes to the bond wire.

Note: Don't do this unless you can ensure that it is safe.
 
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JamesW

TFP Expert
Mar 2, 2011
22,101

This video shows that there is a natural voltage between iron (the walls) and zinc or magnesium.

Metal corrodes when an oxidizer pulls electrons from the metal converting the metal to an oxidized form (rust).

The electrons pushed onto the wall steel will provide the electrons necessary to neutralize the oxygen that causes oxidation.

This means that the iron does not lose electrons and therefore does not rust.

You can measure the natural voltage between the anode and the bond wire to see if it’s enough to protect the walls from corrosion.

Adding a power supply by using a DC milliamp DC voltage in the 1 volt range might help provide better protection.

Note: Don't do anything without making sure that it is 100% safe.

This is not a recommendation. It's just an idea about what type of protection might work if you can figure out how to do it safely.
 

Rattus Suffocatus

Silver Supporter
Jun 5, 2019
1,290
Corona de Tucson, AZ
If you don't care what it looks like (and you won't under a liner).. I have had good luck with this stuff and other brands that are equivalent...

You might be able to transition off to cold galvanizing paint, but that will delay the inevitable more.. you might be able to paint over the rust reformer stuff with cold galv though so it looks new underneath.

I have to admit I am not totally sure about using this on "white rust" but on real iron oxide rust it does a good job at stopping the continuation of rust formation. You want to leave the oxide layer on, but remove loose chunks if you decide to try it. It more or less turns the rust layer to plastic so even though it's ugly it stops further corrosion where it has been treated.

Bummer, man...
 

JoyfulNoise

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May 23, 2015
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Do you know anything about powered anodes?

I wonder if applying power could help protect the walls?

Since it’s a pool, the design would have to be safe and not present a risk.

Maybe a battery in series in the bond wire between the wall and the anode to help increase the voltage pushing electrons towards the walls?


This is used on water heaters. So, I would suspect that it's safe. Maybe contact the company to see if it would work for your application.

It looks like the Corroprotec is 24 volts dc, but I suspect that any voltage between 1 and 24 volts dc would be sufficient to help protect the walls.

Impressed cathodic current protection (ICCP) has been around a long time in the buried storage tank industry. It’s tricky because you really have to design the anodes and power delivery to optimize life time. If you push too much current, you’ll dissolve the anodes in a short order. If you apply too much voltage, you’ll passivate the anodes and they’ll stop conducting. The anodes typically need to be buried in a media that allows for good ion exchange, usually a mixture of bentonite clay and sulfate salts. Finally, I’d be worried about powering anything attached to a pool of water with people in it .... seems risky to me.

I think the rustoleum route is probably to most advised fix.
 

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JamesW

TFP Expert
Mar 2, 2011
22,101
I agree that it needs to be safe without a doubt.

I think that I will try a test setup on a closed pool with a power supply in the 5 to 12 volt dc range and see what type of current it creates.

I will let it run for a few weeks to see what happens to the anodes and if the current changes over time.

I think that I have three anodes that I can put in different conditions to see if it makes any difference.

I suspect that low voltage dc should be safe enough.

The powered anode for a water heater is 24 volts and it goes to the house water supply.

SWGs have 24 volts at the plates.

Maybe if there is a fuse to limit the amp level to about 1 amp, that would help keep it safe.
 
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JoyfulNoise

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I agree that it needs to be safe without a doubt.

I think that I will try a test setup on a closed pool with a power supply in the 5 to 12 volt dc range and see what type of current it creates.

I will let it run for a few weeks to see what happens to the anodes and if the current changes over time.

I think that I have three anodes that I can put in different conditions to see if it makes any difference.

I suspect that low voltage dc should be safe enough.

The powered anode for a water heater is 24 volts and it goes to the house water supply.

SWGs have 24 volts at the plates.

Maybe if there is a fuse to limit the amp level to about 1 amp, that would help keep it safe.

Bag one of the Mg anodes in a cotton bag or tee shirt and use a mixture of 2:1:1 bentonite (cat litter) : sodium sulfate : gypsum (calcium sulfate). Surround the anode with the mixture and keep the anodes in moist soil.
 
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jimmythegreek

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Morris Cnty NJ
I've had good results with rust converters. Zero rust is good as is por15. I beleive rustoleum makes one too. Usually it's the bottom part of the panels that goes bad first which is the line of where the concrete collar is.
 
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JoyfulNoise

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I've had good results with rust converters. Zero rust is good as is por15. I beleive rustoleum makes one too. Usually it's the bottom part of the panels that goes bad first which is the line of where the concrete collar is.

That would consistent with the high solubility of zinc as pH increases. Concrete slurries are very high pH until they cure. The high pH of concrete in contact with galvanized steel will weaken the zinc coating. A corrosion inhibiting paint or some type of barrier film should be used to separate the cement slurry from the steel wall.
 

JamesW

TFP Expert
Mar 2, 2011
22,101
Zinc anode in the ground connected to the bond wire 490 millivolts dc and 700 microamps dc.

Added 9 volt dc rectifier increased the current to 12 milliamps.

That's 17 times more current flow.

Will it do anything worthwhile?

Hard to tell in an uncontrolled environment.

I don't see any risk, but I wouldn't recommend that anyone do it.
 
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JoyfulNoise

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Zinc anode in the ground connected to the bond wire 490 millivolts dc and 700 microamps dc.

Added 9 volt dc rectifier increased the current to 12 milliamps.

That's 17 times more current flow.

Will it do anything worthwhile?

Hard to tell in an uncontrolled environment.

I don't see any risk, but I wouldn't recommend that anyone do it.

Did you measure the mass of the anode before you started? If the zinc anode is easy to remove, you can measure its weight periodically to see if it is decreasing.

Can you monitor the current and voltage periodically? If the power supply is in constant current mode, you’ll see the voltage drift up if the anode starts to become polarized.
 
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JamesW

TFP Expert
Mar 2, 2011
22,101
I didn't weigh the anode, but I can check it periodically to see if it's corroding.

Below is the anode. It's probably too small to do much good, but it will be an interesting test.


The power supply is a small 9 volt dc supply.

I will check the current periodically to see if it changes.

For anyone with galvanized steel walls, it would probably be worthwhile to bury a zinc anode near each wall and connect it to the wall or maybe just bolt the anode directly to the wall. A one or two pound anode on or near each wall would probably provide worthwhile protection.
 

JoyfulNoise

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Yes, welding the zinc or magnesium anode directly to the panel would provide decent protection. Attaching with wiring is less desirable because contacts can become degraded. If it were done at the manufacturer’s plant, it wouldn't be too difficult to attach a few smaller anodes per panel to give good coverage. Might add to the cost but I bet it wouldn’t be exorbitant. Zinc and magnesium are cheap enough to buy in bulk. Automating a placement and welding process would entail equipment costs but that’s going to get repaid over time. Seems like an obvious engineering enhancement to me .... I guess “cheap” is more important than “correct” to them ...
 

Enzodast

Active member
Jul 22, 2020
33
Connecticut
Did your installer line the walls with styrofoam to sit between your panels and liner? Obviously I don't see it in the photos did you take it all off when they removed the liner? Good luck on the rust protection problem I feel terrible for your situation
 

91stealthes

Member
Apr 23, 2019
22
Long Island, NY
Did your installer line the walls with styrofoam to sit between your panels and liner? Obviously I don't see it in the photos did you take it all off when they removed the liner? Good luck on the rust protection problem I feel terrible for your situation

Yes, walls were lined with styrofoam, you should be able to see this in the photos. It was not removed when they attempted to change the liner.
 

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