Posted by Clint Combs on August 13, 2010 at 6:05pm
Today I had a customer tell me that a Vitamin C placed on an iron stain in a plaster pool will loosen the stain enough that it can easily be brushed away in 20 minutes. I would guess that it is the Ascorbic Acid that is key. Has anyone tried this themselves? How did it work for you?
I have not used vitamin C as a full treatment, but have used it to diagnose the problem. Typically I recommend that the consumer put a chewable vitamin C tablet where the staining is. If the tablet removes the stain then I am confident that the ascorbic acid will remove the stain. This is the best way to take care of your customer without potentially wasting money on a stain treatment that may not work.
In response to Richards reply I have used ascorbic acid to remove iron and copper staining effectively. Manganese deposits tend to be treated better by a combination of a stain preventer (example natural chemistry Stain Free) and a metal sequestering agent.
Haven't tried this treatment yet. You can find powdered Vit C at your local health food Or supplement store. Don't use Ester C as is it much less acidic. Best of luck...
Well, I am not experienced with ascorbic acid, but have used citric acid to remove ferrous and many organic stains. Have used it both on plaster and on quartz with some success. As with no-drain acid wash, it's wise to partially drain the pool and refill with fresh water. Citric acid is readily available and not costly.
Yes! We recommend this as a test to see if the stain can be removed using a product like Stain Free by natural Chemistry. It works particularly well on copper and other metal stains.
Yes, I've tried this as have dozens (if not more than a hundred) of other pool owners at Trouble Free Pool (TFP) and it works if the stain is not too old. In fact, for more than a spot treatment, one can buy ascorbic acid powder directly to treat an entire pool. It's a reducing agent as well as being somewhat acidic. There are other reducing agents such as oxalic acid that are less expensive and can also work, but usually do not work as well.
If you look at the chemicals inside most stain removal products, they almost all contain a reducing agent and many are either ascorbic acid or oxalic acid. Note that as a reducing agent it will react with chlorine so is, in effect, a chlorine neutralizer. So you wait until your chlorine level is low before doing a full pool treatment; otherwise, you waste a lot of expensive ascorbic acid neutralizing chlorine. Since the chlorine level will be zero during the treatment, you want to also use an algaecide such as PolyQuat 60 to help prevent algae growth. In fact, a large dose of PolyQuat 60 will also consume some chlorine (but won't destroy PolyQuat's ability to inhibit algae -- the chlorine just breaks up the polymer into smaller pieces) so could be added first to also lower the chlorine level.
The ascorbic acid treatment for the pool will lower the pH and that also helps keep the metal in solution. A metal sequestrant can then be added or one can try the new CuLator metal remover that was just posted in a blog on this forum. Note that any excess ascorbic acid in the water will result in a high chlorine demand so it will take extra chlorine to be added before you start measuring a Free Chlorine (FC) residual.
The Ascorbic Acid approach works best for iron stains because it reduces the ferric form of iron that is typically combined with oxide-hydroxide (i.e. rust) into a more soluble ferrous form that is also more readily bound by most metal sequestrants. The treatment doesn't work as well with copper, though some have used it anyway -- probably the lower pH helps more than the reducing agent in this case, but I'm speculating here.
More on the ascorbic acid treatment process is here.
Comments
The ascorbic acid treatment has been effective on all pool types as long as the stain had not been allowed to linger longer untreated.
In response to Richards reply I have used ascorbic acid to remove iron and copper staining effectively. Manganese deposits tend to be treated better by a combination of a stain preventer (example natural chemistry Stain Free) and a metal sequestering agent.
If you look at the chemicals inside most stain removal products, they almost all contain a reducing agent and many are either ascorbic acid or oxalic acid. Note that as a reducing agent it will react with chlorine so is, in effect, a chlorine neutralizer. So you wait until your chlorine level is low before doing a full pool treatment; otherwise, you waste a lot of expensive ascorbic acid neutralizing chlorine. Since the chlorine level will be zero during the treatment, you want to also use an algaecide such as PolyQuat 60 to help prevent algae growth. In fact, a large dose of PolyQuat 60 will also consume some chlorine (but won't destroy PolyQuat's ability to inhibit algae -- the chlorine just breaks up the polymer into smaller pieces) so could be added first to also lower the chlorine level.
The ascorbic acid treatment for the pool will lower the pH and that also helps keep the metal in solution. A metal sequestrant can then be added or one can try the new CuLator metal remover that was just posted in a blog on this forum. Note that any excess ascorbic acid in the water will result in a high chlorine demand so it will take extra chlorine to be added before you start measuring a Free Chlorine (FC) residual.
The Ascorbic Acid approach works best for iron stains because it reduces the ferric form of iron that is typically combined with oxide-hydroxide (i.e. rust) into a more soluble ferrous form that is also more readily bound by most metal sequestrants. The treatment doesn't work as well with copper, though some have used it anyway -- probably the lower pH helps more than the reducing agent in this case, but I'm speculating here.
More on the ascorbic acid treatment process is here.