Seemingly unavoidable iron problem in water

[genespleen]

Iron in water, unavoidably

Hi All,

Okay, I have a problem. We have a very old (c.1930) in-ground swimming pool, which has a built-in iron ladder (built-in, as in sunk into the concrete wall) and an iron drain-fitting. When we bought the house and drained, scrubbed, and painted the pool last year, I got the surface rust off of both before painting them, and for last year, that sufficed.

But this year, the rust returned: the ladder rungs have pits and other surface irregularities with plenty of corrosion, and the drain-fitting has several places around its circumference that are rusting as well. This means I have a seemingly unavoidable--and high--iron content in the water. I've not had the water tested, but it tends toward a clear green tint and as much as I try (using metal remover and keeping the Ph on the lower side: 7.2-7.1 or so), there is always a slight greenish tinge.

This fall, I plan to drain the pool for repainting in the spring, and I suppose at that time I could simply saw off and remove the ladder. But does anyone have ideas about other possible solutions?

best wishes,
David

 

[shortdogOH]

Re: Iron in water, unavoidably

As this is a reoccurring problem, your solution of removing the source of the problem seems the best. Not sure what type of paint you used, but you might experiment with a rust inhibiting or waterproof brand and that might get you by for more than a season or two.

Interesting that iron oxide (rust) would cause a green tint. My guess is there may be something else going on as well.

Just some thoughts.

 

[genespleen]

Re: Iron in water, unavoidably

Thanks Shortdog--you may be right about other things going on.

I'm going to "move" my question to another, more-trafficked, subform to see what others have to say.

 

[genespleen]

Hi All,

I posted this in the subforum "Chemistry 201" but thought I'd move it here, as I think that forum doesn't get as much traffic as this one. Apologies for double-posting.
Merged Topics to avoid double-posting. Butterfly
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Okay, I have a problem. We have a very old (c.1930) in-ground swimming pool, which has a built-in iron ladder (built-in, as in sunk into the concrete wall) and an iron drain-fitting. When we bought the house and drained, scrubbed, and painted the pool last year, I got the surface rust off of both before painting them, and for last year, that sufficed.

But this year, the rust returned: the ladder rungs have pits and other surface irregularities with plenty of corrosion, and the drain-fitting has several places around its circumference that are rusting as well. This means I surely (?) have a seemingly unavoidable--and high--iron content in the water. I've not had the water tested, but it tends toward a clear green tint with plenty of yellow-green sediment. As much as I try (using sequestrant and keeping the Ph on the lower side: 7.2-7.1 or so), there is always a slight greenish tinge to the water. (Earlier this summer I had metal staining on the pool walls, which I removed using the absorbic acid treatment followed by sequestrant, but the greenish tinge has returned. I've repeated application of sequestrant, because I just do not want to let the TC go to zero for that application.)

This fall, I plan to drain the pool for repainting in the spring, and I suppose at that time I could simply saw off and remove the ladder. But does anyone have ideas about other possible solutions?

Again, I have not had the water tested for metals, but I can't imagine that the corrosion is not having significant effects.

best wishes,
David

 

[Patrick_B]

Perhaps when you repair they can blast it to white metal and preserve it with some sort of extra durable coating. However, as pessimistic as it sounds, I don't think you'll ever be able to keep it from coming back to where you are now. Maybe not for a long time, but eventually it will return. If you remove them, you'll obviously have less in the water so that would be the thing to do, but who knows how much of the wall you'd have to remove to get them out. If you were lucky, they wouldn't be bent for anchoring. And the drain is the same? Same situation there requiring a lot of removal possibly. Iron is a very common cause of green tinged water. It would be good to know if you had any in your fill water as well. Hopefully, someone will offer you more hope. Sorry to sound so negative, but I feel for ya. I'll hope for the best!