Thoughs on Theoretical Metal Stain Removal (Manually). Could This Work?

phappy

Well-known member
Aug 25, 2013
45
I'm interested in your thoughts as to if you think this could work.

1.) I have iron in my pool. The plastic white step entry into the shallow end is entirely stained, the white plastic fittings are stained, the filter basket, as well as the deep-end "Joints" where the bottoms meets the sides.

2.) Since I see these stains, does this mean that ALL (or at least MOST) of the metal is NOT in solution? (Basically, has it all "settled-out" and caused the stain?)

3.) If so, if i were to somehow use an Ascorbic Acid to scrub a section...while ALSO simultaneously using a suction hose to remove the water right above the area I'm scrubbing (basically to hover over that area). The hose would remove the water completely from the pool as waste.

4.) Would this then pretty sufficiently remove the metal form the pool? I realize some of it would still be in solution, as you wouldn't be able to vacuum it all out as it was being scrubbed. But would "MOST" of it be removed?

Just wondering if I can rig-up a device that scrubbs using ascorbic acid, yet also sucks out the water that it scrubs. And wondering if this is a viable solution to just using ascorbic acid and putting the metal back into solution (only to re-settle, need to be treated with sequesterant, etc = lots of $)
 

duraleigh

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2. No you still have iron in solution because your source water has iron. refilling will constantly add more iron to your pool.
 

phappy

Well-known member
Aug 25, 2013
45
2. No you still have iron in solution because your source water has iron. refilling will constantly add more iron to your pool.

Thanks for your reply, duraleigh. I understand your point.

But the water I use to refill the pool isn't my question at this point.

I'm just talking specifically about the water that is already in the pool. When I see the visible stains, does that then mean that ALL the iron is contained in those visible stains & that there shouldn't be any in the rest of the pool water?

- - - Updated - - -

Ah..wait, I'm re-reading your reply.

Do you mean that the "source water" IS the water already in the pool? I think I understand better now. I thought you just meant the water that I'm going to use to refill the pool, to replace the water I'm sucking out.
 

JoyfulNoise

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May 23, 2015
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Tucson, AZ
Just because you have iron stains (solid) does not mean there is no iron ions (Fe2+) in solution. Your water is essentially over saturated with metals and, at your pH, the metals are coming out of solution. It's an equilibrium condition though, the amount of metal that scales out is based on concentration and pH. So if your concentration goes down as metal is scaling out, the scaling essentially stops once the equilibrium point is reached. That's a lot like what the AA is doing - it is lowering the pH (and exerting a chelation "pressure" on the iron) which shifts the local equilibrium making the solid iron (scale) more soluble in water.

I suppose your device could work but it would be hard to seal that water flow against the surface and I don't think it would work very efficiently. That is to say, you'd lighten the stains a bit but lose a lot of discharge water in the process.
 

basod

Gold Supporter
May 27, 2015
255
Mount Cheaha Alabama
I've been playing around with direct AA treatments. Iron stains seem to adhere somewhat to terry cloth towels that have been soaked in an AA solution and dried.
If you use a sock full off vitC pills it will remove the stains and place them back into solution off the towel continuously. By wiping and removing the towel then rinsing in a mild MA bath rinsing and resoaking in the AA solution you can progressively remove some iron scale and not put it back into the pool water.

All of this work is in vain unless you control the source iron - whether it be fill water or something rusting in your pool
What you're try to do is remove the metal stain and pump it out of your pool on a controlled vacuum - sounds like a good idea, but it's probably similar to doing a whole pool AA treatment and partial drain& refill.
Assuming you're not adding additional iron through the fill water.

You can continuously remove metals(specifically iron) with side-stream filtration see this thread http://www.troublefreepool.com/threads/120372-Side-stream-metal-removal-filter-Experiment
 

phappy

Well-known member
Aug 25, 2013
45
I've been playing around with direct AA treatments. Iron stains seem to adhere somewhat to terry cloth towels that have been soaked in an AA solution and dried.
If you use a sock full off vitC pills it will remove the stains and place them back into solution off the towel continuously. By wiping and removing the towel then rinsing in a mild MA bath rinsing and resoaking in the AA solution you can progressively remove some iron scale and not put it back into the pool water.

All of this work is in vain unless you control the source iron - whether it be fill water or something rusting in your pool
What you're try to do is remove the metal stain and pump it out of your pool on a controlled vacuum - sounds like a good idea, but it's probably similar to doing a whole pool AA treatment and partial drain& refill.
Assuming you're not adding additional iron through the fill water.

You can continuously remove metals(specifically iron) with side-stream filtration see this thread http://www.troublefreepool.com/threads/120372-Side-stream-metal-removal-filter-Experiment
Basod, terrific post. Thank you first for putting in the effort to try to find solutions, and then for sharing your results.

When you say you soak the towels in an AA solution, this is just AA & water right? The only AA I have is in powdered form which I ordered from a an online spice company.

And then you are able to use these AA-soaked towels under the pool water while you scrub? And they still seem to retain (at least some) of the metal on the towels?

You seem to be a whiz at plumbing. You mentioned making up a diagram/pdf of your metal filtering plumbed system?

Thanks again for your help.
 

basod

Gold Supporter
May 27, 2015
255
Mount Cheaha Alabama
Phappy the rags are soaked in an AA solution that is nearly saturated just about when no more will dissolve. Then dried and I dive wipe as much as possible return to the surface test rinse the towel in tap water to verify the stain will not lift off the towel. I've found if you rinse the towels in a bleach water bucket the iron will come into solution but not all of it. The diluted MA water will remove the remaining iron stains then rinse in clean water and re soak in the AA solution dry and repeat the process.
I've seen a few videos where people use pump sprayers with Dissolved AA underwater and I might try a modified version but with some kind of hard floor mop duster.