Stain removal via ascorbic acid treatment

Info is correct, but method needs rewriting
[*]Few people seem to be able to follow this process successfully, because it is too hard for most. Unfortunately,I don't know a simpler method that actually works!

Ascorbic treatment for stains
(original by mbar, posted by aylad, and updated by PoolDoc in 2012)

BEFORE YOU START, YOU MUST:

• Complete the Pool Chart
• Have K2006 test results on your pool AND your fill water.
• Have a calcium hardness level below 300 ppm.

Some people who've tried to use this method have had failures. We're trying to work out why. We don't want ANYONE to do this, if it's not going to work for them. Pool stores are happy to sell you much easier (and cheaper) stain removal methods that don't work! ;)

Currently, the problems seems to be result from high calcium levels interfering with HEDP. So, before you start this process, we want to look over your shoulder, and be as sure as we can, that it's going to work for you.

Here are some basic facts about this process that you need to understand, BEFORE you start. The pool industry misrepresents what various pool chemicals do, but perhaps never more so than with stain and metal control products. Here's what you need to understand.

1. Stains are NOT metal IN your pool water; stains are metal products ON your pool's surfaces.
*It's possible to have a badly stained pool, with ZERO metal in your pool water.*

2. Metals can be IN your pool water, but not be ON your pool's surfaces anywhere.
*You can have high metal levels in your WATER but NO stains on your pool.*

3. You can remove stains in 2 ways. You can remove the SURFACE that the stain is ON; that's what acid washing does on concrete pools. OR, you can DISSOLVE the metal products OFF of the surface and put the metal BACK INTO the pool water. That's what ascorbic acid (Vitamin C) does.

4. When you REMOVE a stain, you usually do NOT remove the metals from your pool; all you do is CHANGE their location, moving them from the surfaces, back to the water.

5. While metals in pool water may not have stained your pool, if there are metals in the water, the potential for staining is ALWAYS present. Even very LOW levels of metals will stain, when conditions are right for stains to form.

6. Sequestrants mostly do NOT remove stains; instead what they do is KEEP metals IN your pool water.

7. The difference between a sequestrant and a chelant is about words, not chemistry. "Sequestration" is what "chelants" do, when you add them to pool water. So, when you refer to HEDP as a "sequestrant" you are referring to what it DOES; when you call it a "chelant" you are referring to what sort of thing it IS, chemically speaking.

Sequestration of metals, like sequestration of a jury, means taking something, putting it somewhere, and keeping it there. With juries, the 'somewhere' is the jury room; with metals, the 'somewhere' is IN your pool water.

Chelation describes the chemical nature of the material: at a molecular level it has 'claws' (Greek chêlê) that grab onto metal atoms, and keep them dissolved.

8. CuLator contains small beads of plastic material that apparently has the property of grabbing dissolved metals -- even metal that has been sequesterded by use of a chelant.

9. Thus the complete sequence described here has 4 parts:

• Add ascorbic acid to re-dissolve the metals.
• Add HEDP to sequester (keep in the water) the metal dissolved as the chlorine is restored
• Discard the metal-containing CuLator bags to REMOVE the metal.

Each part is ESSENTIAL, to actually remove the metals from your pool! If you miss a step, or mess it up, the odds are, the metal will REMAIN in your pool somewhere, just waiting to cause more problems.

10. There's one more aspect to consider. The metal got IN your pool from SOMEWHERE, and the odds are, if you don't make a plan to resolve that issue, the stains will re-appear at a later date, because metal will continue to be added to the pool. There are X common sources of metals in pools:

• algaecides and copper containing chlorine blends can add copper
• well water can add iron, manganese or rarely, other metals
• utility water can add iron
• pool heaters and other equipment can add copper or iron, if pool pH gets very low.

So, part of solving a pool's metal problems is finding the source of the metal, and dealing with that source on a regular basis. For example, well water users may need to add a small amount of HEDP every time they add water to their pool.

• Verify, using vitamin C tablets, that ascorbic acid (vitamin C) will remove your stains, before you go buy the stuff listed!
  
  
• Purchase a K-2006A or K-2006C testkit, and learn how to use it BEFORE beginning this process. Do not even THINK about trying this with test strips or a 3 or 4 way kit! (A K-2005 is OK, but ONLY if you already have a K-1515 on order! You can get started with a HTH 6-Way Test Kit, but ONLY if you already have a K-2006 on order!)
  
  
• Let your chlorine drop to 0.0 ppm.
  
  
• If your pH is above 7.4, lower it at least to that level.
  (if there is chlorine in the water it won't hurt, it will just eat up the ascorbic acid, so you will need more to get rid of the stains.)
  
  
• Put the filter on circulate, not filter.
  (Remove your cartridge if you have cartridge filter. If you have a DE filter with no multiport valve, you MUST continue to use DE, but change the polyquat frequency to every 2 days.)
  
  
• Add polyquat algaecide to avoid algae problems while the chlorine is low.
  (Per 10K gallons, if you have no algae, use 1 cup every 3 days. If you have some algae present, use 2 cups every 3 days. If you have much algae . . . wait till the algae is gone!)
  
  
• Add 1/2 to 1 lb ascorbic acid per 10K gallons
  (I like to go lighter on it and see if all the stains lift off before adding more.)
  
  
• Use a cup and go around the perimeter of the pool and drop it down the sides as you go.
  
  
• Let the ascorbic acid circulate for 1/2 hour.
  (You will be amazed how the stain just disappears before your eyes. )
  
  
• If the stain is not all gone after 1 hour, leave the filter on circulate and add more ascorbic acid close to where you still see stain. Leave it on circulate until all of the stain is gone. Do not add more 2 lbs of ascorbic acid per 10K total.
  
  
• As soon as the stain is gone, add HEDP at the rates shown below.
  
  
• Put the filter back on filter and leave it on 24/7 for at least the next week.
  
  
• If you have purchased a CuLator packages, add it to your skimmer AFTER installing a skim sock.
  
  
• Test your pH; if it is below 7.0 use 20 Mule Team borax to raise it to 7.0, but no higher.
  (1/2 box per 10K gallons, added slowly to the skimmer with the pump running.)

What to expect:
Ascorbic acid will bring your ph down, and sometimes the alkalinity. After 24 hours you can start to re-balance the water. Use borax to raise your pH -- 1/2 box per 10K gallons, added slowly to the skimmer.. Make sure you test in between, because you don't want your pH to go higher than 7.2.

Once your pH is in range, you can start to bring up your chlorine -- SLOWLY. It will take a lot of chlorine - I prefer to use bleach only at this time, and try to take it up to your minimum chlorine for your CYA according to the "best guess chart".

As you slowly raise the chlorine, watch for stains starting to form. If you see stains, make sure the pH is no higher than 7.2, and add more sequestering agent. You should see the stain lift in a couple of hours.

Do not shock! Do not shock for at least 2 weeks! Make sure you keep your ph low for (7.2) for a week or two. Once your chlorine starts to hold, it means that you have used up the ascorbic acid in the water and it will be easy to re-balance the pool back to your regular parameters.

Here are two important notes: High ph along with high chlorine will precipitate any metals that are not sequestered out of the water and on to the surface of the pool again. If this happens take the ph back down to 7, or 7.2 and add more sequestering agent. This should lift the stain off. You can add polyquat 60 to the water before starting the stain treatment to avoid getting algae while the chlorine is low.

Links to Amazon for all the products are below. You do NOT have to buy from Amazon, but if you buy locally, be very careful to make sure you get the EXACT same product. We get a commission on Amazon sales, so all things being equal, we'd prefer that you buy from Amazon. However, if you need it now, or find a great price locally, feel free to use our links to make sure you get the RIGHT product . . . and then go ahead and buy locally.

Do NOT confuse citric acid with ascorbic acid; it is cheaper, but less effective and it has some nasty reactions with chlorine. We have not heard of ascorbic acid being available locally, except as Vitamin C pills, which are much less concentrated. Locally sold liquid stain / scale products may be HEDP . . . or any of another of other chemicals, some of which are pretty ineffective. If you buy locally, make SURE you match products. Polyquat used to be available locally, but has become very hard to find. Read our polyquat page FIRST, if you want to buy locally.


Order links:

K-2006A
K-2006C

If you have a K-2005, order a K-1515
If you have a HTH 6-Way Test Kit, order a K-2006

Ascorbic acid - 1-5 lbs @ Amazon
Ascorbic Acid Vitamin C Powder USP Pharma Grade 6 Lbs @ Amazon

Kem-Tek 60% polyquat @ Amazon
Nava 60% polyquat @ Amazon

Jacks Magic The Pink Stuff 1qt (60% HEDP) @ Amazon
20% KemTek HEDP @ Amazon

Poolmaster 16242 Poolmaster Skimmer Basket Liner

I am going to try the ascorbic acid method for stain removal Ben last edited this week. Once you add the sequestering agent (I also did not see the amount to add per 10K gal), how long before you can begin to add chlorine back. Maybe I missed something. Everything else in procedure seemed clear. Wanted to get a feel of how long before swimming can resume -chlorine at minimum per best guess chart. Going to order the materials this weekend from Amazon. Thanks for all the help.

You can add the sequestering agent per the directions on the bottle. You can swim as sonn as your pool starts to hold chlorine. The ascorbic acid will not hurt you, you just want your water to be sanitized. Sometimes if you have a high calcium level, you water may get cloudy- it is just precipitating out of the water and will clear up with bleach. Sometimes it takes a lot of bleach until it eats up the ascorbic acid. Just make sure while adding bleach you don't take it to shock levels - let us know if you have any questions,

Marie