Ascorbic Acid Treatment

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SupaDave

SupaDave

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Bronze Supporter
Nov 25, 2016
37
Bethlehem, GA
First of all, let me thank MBAR for their write up of ascorbic acid treatment from years back. I am on a well here in South Florida and do have some iron in my water but never enuf to stain household fixtures or my vinyl pool liner. Sure enuf, after 25 years of maintaining this pool without stains, I got some iron staining after finding and following the TFP method. Not complaining mind you, just sayin.... I'm very happy with the TFP method and will continue to practice. I guess it happened due to my rookie mistake of trying to keep my FC levels at the proper SLAM levels ( FC of 24 with CYA of 60 ) for several days while trying to get rid of an algae bloom, but not paying attention to my pH levels. Previous to finding TFP, I had never raised my FC that high and subsequently never caused iron to stain. My bad, no one else's.

Anyhoo... Followed MBAR's ascorbic acid treatment and WOW I have my pretty blue liner back, all the stains are gone!!!:thumleft:
As I sit here writing this I am about 1 hour post putting Jacks Pink stuff in pool after AA. DE filter is running. Polyquat 60 added. Questions:

1. So the iron is now off my liner and now in solution? How do I get all that sequestered iron out of my pool? I am on a well and have no problem draining and adding water..........Thinkin bout lowering my CYA a bit anyway.
2. Since this is the first time in 25 years that I have had this iron staining am I correct in assuming it was caused by the high FC levels and high pH and my rookie mistake during SLAM?
3. And if #2 is correct, can I assume that I've always had iron in my pool water, but chemistry did not allow it to stain?
And lastly, am I now married to using sequestrant maintenance on a regular basis? or will ridding my pool of the now sequestered iron and monitoring my pH in relation to my FC do the deal?
And last, lastly, MBAR advised to raise FC "slowly" while maintaining pH at 7.2. How slow is "slowly"? Hours, days?....
And how often do I need to repeat the Polyquat 60 while raising my FC?

Sorry to be so long-winded, but I sincerely want to thank everyone on TFP for their selfless and informative help.
I'm so glad I found ya'll. Thanks again, MBAR.
Dave
 
Good morning. While Kim is optimistic in her assessment of my metal prowess, i should first say its always entirely possible for my best guesses on metal issues to be wrong ;) But I have wrangled with various metal mysteries over time, and have directly spoken with various companies who make the sequestrants and read up a fair bit on the subject ;)

So I will attempt to answer your questions.

-- But easy one first: By "slowly" in raising FC its to not overshoot...don't take days, just add FC to your normal level...check again in a few hours. If there's AA left over, it will use up the FC and you'll need to add again. Just don't overdose it.

And regarding this:
2. Since this is the first time in 25 years that I have had this iron staining am I correct in assuming it was caused by the high FC levels and high pH and my rookie mistake during SLAM?
Click to expand...

-- This was likely a two-part event...iron at lower levels was always in the water, but over time accumulated to higher levels, then was oxidized out of solution by the slam. In general, its best to maintain chemistry in order to avoid a slam at all when you have metals ;)

So now;

1. If you applied enough sequestrant after your AA treatment, yes, the iron will be back in solution. Things that may make staining come back over time are:

A. Sequestrant wearing off...chlorine gradually breaks it down, hence the need to replenish
B. High ph. Its best with metals to attempt to keep ph on the lower side, eg 7.2-7.4.
C. Concentration of metals increasing...this will depend on how much iron is in your source water, but over time, as your water evaporates and more is added from your well, your levels can increase in concentration.

Some of the chemists involved in making sequestrants believe their products will help the filter filter out some of the iron as it binds with calcium. This is theoretically viable. The general TFP view of this has been that such action is baloney, and that if you have metals, you have metals. I personally think its a bit more complicated than that. Eg. I think "some" iron does carry out with calcium, and that in general, sand filters are capable of reducing iron concentrations to some extent, especially when the iron has been oxidized. But there are too many variables to track.

Which is why its hard to say for certain whether top up is better in your case....I don't know if your well water is lower in iron than your pool water right now, and when you use sequestrant, you're not likely to show any iron even if you had it tested ;)

Example...your well doesn't stain, but you don't mention whether you have a home water softener.

If you don't, and your well doesn't stain your dishwasher, toilet etc., then I predict your well has less than .3 ppm iron...probably a good deal less ;) .3 ppm is the magic number where staining can occur, although smaller amounts can stain if ph is really high or if iron oxidized via high FC.

There are also 3 types of well borne iron, ferric (oxidized particles), ferrous (invisible in solution) and bacterial iron. Prefiltering water works to some extent on reducing ferric iron, less so on ferrous.

In your case, since you've gone 25 years without staining, and since our best guess is that your well is very low in iron, a partial water change may in fact reduce any future amount of sequestrant you'd need.

And if you avoided needing to slam and controlled your ph, together with ample rain in Florida, you might be just as trouble-free getting off the sequestrant habit.

You could just observe for a few weeks for the first sign of a hint of staining, and only add sequestrant at that point (which usually will remove faint staining). Then decide.

Or if your in an experimental mood, and want to start testing for iron, I could post a week-long bucket test method for you to force sequestrant in a bucket to wear down and test. My hunch is that's way more foolin around than you need ;) but just post back if you want the info and I'll dig it up ;)
 
Swampwoman-

Funny you should mention my well water iron levels, as I just had an expensive analysis done. I do have a water softener, but obviously it only does the house water. My iron levels were 0.14 mg/l as you expected, my hardness was 190 mg/L, Ca 72 mg/L.
My current #’s as of 15 mins ago:
FC=0 (DPD powder does not even change color of water sample)
pH= <7.0 (Sample color is yellow on my Taylor Kit, value is below what I can measure)
Alk= 40
CYA=30 (measured x 2) Which is very weird, as prior to the AA treatment, I was around 60-70 and planning on lowering it anyway….. Possible the chemicals I added affected CYA?
Do I need to reapply Polyquat 60 (and how often) while raising my FC? as several people have remarked that it took “several days” to get their FC to hold post AA treatment and I am obviously trying to avoid algae. As I mentioned, I think I would like to do a partial water change, maybe 50% or so, to rid the pool of sequestered iron. Currently, I only have put in a Kg of AA, one bottle of Polyquat 60, and 3 bottles of Jacks Magic Pink about 18 hrs ago. Should I do the water change prior to addressing my FC levels, or ?
Thanks for your help.
Dave
 
Hi there. In your case, then, if you can get Er done today, do the partial water change, then dose, check, dose to get rid of any leftover AA, which will be diluted. If you were going to wait a day or two to do the change, I'd personally dose, test, dose to regular FC levels today...because at al costs you don't want to have to slam again ;)

In the past, its only taken me a few sessions of dose, test, dose to get the FC to hold, but that's in proportion to how much AA you've used and size of pool I believe.
 
Swampwoman:

SupaDave has asked the exact questions I've had in my head..having just started the TFP method and with some staining issues. I'm not trying to hijack..just piggybacking on the same questions...Sorry if this is wrong to do...When you say you may need to add more sequestrate later..is this monthly...or every other month?.....weekly?...and how do you know you need to add more sequestrant? Having just got my pool to TFP clear...I'm nervous as heck to lower FC to zero in order to use Jack's magic ID kit...so I'm reading as much as i can before trying to tackle this.
 
It truly depends on the concentration of iron in your pool together with ph, etc.
generally, a small weekly dose is best if swg. Some folks add a larger dose monthly. Other simply wait until they see faint evidence of stainng, eg super light on white steps...then add a fresh dose.

If you add lots on the front end, you'll need to dose less frequently in my experience. Results really do vary, so you can either follow the mfgs instructions on bottle OR wait for a visual cue...the latter is usually cheaper ;)
 
Swampwoman-

Thanks for your quick reply. It's raining and cloudy today, so no can do on the draw down.
I was so worried about algae returning that I started working back to my TFP levels. Here are my #'s so far:
Fri 10:30 am (20 hrs after AA and Polyquat) FC=0 pH<7 alk=40 cya=30 Added 80 oz Cl.
Fri 12:30 pm FC=1 pH=<7 alk = 40 Added 80ox Cl + one DE cups worth of Soda Ash for pH.
Fri 2:30 pm FC=2.5 pH=<7 alk = 50 cya=30 Added 80ox Cl + one DE cups worth of Soda Ash for pH.
Will do another check/dose at 4:30, but I hesitate to say that it looks like my CL is holding.....? Can it possibly be that easy?
And whatcha think bout that CYA #? I would swear it was 60 or so prior to AA treatment and now 30? I could see being off by maybe 10 or so due to inaccurate reading, but 60 to 30? Any ideas?
BTW The pool looks amazing!!! :kim:

D.



D.
 
Bringing your FC back after AA treatment is that easy. I think 4-6hrs of gradual target doses was what it took me last year after a direct AA treatment.

as for the CYA I saw some very similar 30ppm downward swings on the test. Don't fret the CYA is still there retest in a couple days under normal sun light conditions and after you get the pH back up by turning your eyeballs to the surface and FC is holding at stable levels.
 
Well, I must say, the pool looks beautiful, crystal clear, no stains. Thanx everyone for all your help. It's been 12 days since my AA addition and my CYA level is still approx. 30, down from 60-70 pre AA treatment. I am losing slightly more FC daily than normal which I attribute to a CYA of 30. Surely all the AA must be gone by now?
since The pool has been running 24/7 since the AA treatment and pH has been kept at 7.2-7.4. I'm going to add some stabilizer and try to get back to CYA 50.
 

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Well, I guess I spoke too soon. :( noticed the start of a small green algae patch on pool bottom yesterday. grrrr........ I guess my greater than usual free Cl loss was not due to CYA...... Started a SLAM and will keep pH LOW, this time to avoid staining.Brushed. Will confirm with OCLT in a couple of days.
Somewhat confused with this CYA test on the 2006 kit. It is so subjective. I test indoors under fluoro light (its been raining for 10 days strait here in tampa) and hardly any sun. I consistently was getting 30 ppm after several repeat tests. I broke down, went to the pool store. had them test it. They got 50-60 with the slider type test repeatedly. Had them test with MY 2006, they pushed their 50-60 figure, saying "well, the black dot dosent have to disappear completely......" I ordered the Pentair slider deal on Amazon. If my CYA had actually been 50-60 and I was chlorinating at a level commensurate with CYA level 30..... Well.......:confused:
 
GLANCE in.........do NOT look for the dot or you will see it. Inside is not the best BUT you are so right with the rain we have been having you will not be able to test outside for quite a while (Have you see the forecast for this week :shock:).

Pour to the first line (100), GLANCE in, if you see to dot, pour to next line, GLANCE in, keep going until you do not see the dot at a GLANCE! It should be gone when you GLANCE in.

Does this help?

Kim:kim: (oh how I HATE this test)
 
Kim-

Using your method, I still get between 30-40. Oddly enuf, I just received my Pentair Tester a few minutes ago (gotta love Amazon Prime) :)
Several tests via Pentair and I can only get 40 repeatedly. Which is odd, because I just added 4# of dry stabilizer via sock method 6 days ago when my CYA was 30 via the K2006 kit! As I mentioned, the pool store got between 50-60, but I watched them do it and the black dot was still slightly visible. They said " Oh, it doesn't have to be completely gone.... " OMG
BTW I find the Pentair test much easier to use and view, just my opinion. And yes, as I sit here typing, it's raining cats and dogs. :cat:
 
Just took a look at Pool Math. For a 10ppm increase in CYA level for my pool size ( to go from my suspected current level of 40 to 50 ), it requires just about 3# (44 oz) of stabilizer. If I was originally at about 30 as I suspected, and added 4# of stabilizer as I mentioned I did, it would have raised me to "around" 40 ppm or so cya, where I currently am. Goin out on a limb here, but could this suggest I'm doing this test close to correctly? and I actually need to add more Stabilizer? :brickwall:
 
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