Results of Ascorbic Acid Treatment for Stains

[mbar]

I think you probably didn't have enough HEDP in the water for all of the metal, by taking your ph up to 7.3 and your bleach up to 6 it caused the metals to fall out. You probably needed more HEDP, I usually keep the ph on the low side - about 7.0 to 7.2. I have been getting a lot of staining this year even with the culator. I think it is because this year I did not have my pool at the saturation point to have the calcium precipitate out. It seems if when you do the stain treatment, and your water gets cloudy, the metals seem to get filtered out with the calcium precipitate. It is just an observation right now. I am thinking of experimenting by doing this, but I am getting company and don't want a cloudy pool right now. I have been adding a little ascorbic acid and more HEDP when I see the stains start to come back. If you put about 2 cups around the perimeter of the pool, and let the pump on recirculate overnight it should lighten the stains. It will use up more chlorine than average, but it won't be enough to mess with your water balance too much. Make sure you use polyquat and keep your chlorine at the low end of the best guess chart. Take the tabs out when you use bleach. Make sure the tabs don't have anything else added - a lot of tabs do now. It might be where you are getting your metals. I know it is really frustrating, I have dealt with stains for the past 11 years. I used to try to figure out where the metals were coming from, but now I just deal with the stains when they come. I always keep some ascorbic acid and HEDP on hand. I know how you feel, I hate stains too!

[Watermom]

I have to tell you all ----- I have seen Marie's pool in person and it was beautiful! Not a stain in sight!

[mbar]

Thanks! I have learned what works in my pool, you will too.

[JimK]

I'm also going to guess not enough HEDP. Some years ago (around 2006?), before I was aware of this site, I had staining issues on my steps and vinyl liner. My pool store suggested using ascorbic acid to remove the stains then use Jack's Magic Purple Stuff to prevent them from coming back. They told me the metals probably came from the small amount of impurities in the pool salt (I'm not sure of this). I also contacted Jack's Magic also for guidence and info. Jack's recommends you keep HEDP at a certain level to prevent staining, so I ordered a sequest test kit so I would know how much I had in my pool.

The ascorbic acid worked well to remove the stains so I started adding HEDP and testing the sequest levels. Apparently the metal levels were quite high as I kept having to add more HEDP to maintain the recommended levels. Jack's said to keep adding the HEDP until the levels stabilized in the recommended range. I think I went through 1 or 2 cases (!) of HEDP before the levels finally stabilized. Since then I've been adding a maintenance dose each week.

Fortunately the stains did not return during the initial treatment and I've not had any stains since.

Earlier this year I had asked the question about whether or not I still needed to keep adding the maintenance dose of HEDP (Jack's told me their product would allow the metals to be filtered out, but information here seems to indicate that HEDP just keeps the metals in suspension). Ben had me do a bucket test to see if I still had metals, and it appears I do not (where did they go?). So the past month or two I've only been adding half as much HEDP and so far no staining. I may reduce the amount again and see what happens (or not, I really don't want to deal with stains again!).

Hope something in this story is helpful to you.

[PoolDoc]

Just a note to all:

If you suspect you have a CONTINUING source of metal in your pool -- from well water, antique and rusting pool pipes, a deteriorating heater, utility water that contains iron, etc -- you may want to use BOTH a CuLator PLUS small doses of HEDP, every time you fill.

Peroidic products want's you to replace the CuLator monthly. However, based on their patent info, and info on their site, the product should work indefinitely IF:
1. It's not fouled with goop (thus, we recommend putting it UNDER a skimmer sock!)
2. It's not discolored.

To the extent the CuLator works at all -- and we think it does -- you should be able to put a CuLator bag in your skimmer in April and have it last till September, as long as it's neither fouled not strongly covered. The carrier beads might fail in water eventually, though I doubt it, but you might want to replace the CuLator annually, unless you are willing to take a chance.

BUT, you MUST remember that the CuLator ONLY works when the metal is soluble. So, when you add water, add a little HEDP, and try to do it when the chlorine is a bit low. Do NOT add water on top of skimmer tabsl.

Now, this is confusing: you can use skimmer tabs to REMOVE metals, OR you can use the CuLator to do so. But these (tabs vs CuLator) methods are 100% incompatible. Skimmer tabs tend to take metals OUT of solution, upstream of the filter, so they can be filtered. CuLator units remove metals ONLY when they ARE in solution. CuLator can / should be used WITH HEDP; skimmer tabs are likely to fail when HEDP is used.

BUT . . . skimmer tabs are chancy -- you hope the stains / precipitation will come out on the filter, but it CAN come out on the pool, instead.

This is a fairly difficult topic; I hope I've been as clear as is possible.

[Cookieman]

Thank you mbar, watermom, JimK and Ben for the helpful advice from experience. Please check to make sure my summary from all is accurate. Outside of bringing ph/chlorine levels up too high too fast, I did not add enough HEDP, and should not have used to trichor tabs ( in floatie and skimmer opposite of Culator)for chlorine source while using Culator. Stains have continued to darken while I am waiting on another batch of HEDP, Algeacide, and ascorbic acid, so, more questions: Are the skimmer tabs Ben refers to chlorine tabs or tabs for removing metals? The dosage on the KemTek HEDP for my pool is about 2 1/2 quarts per dose. I only ordered 2 doses, but sounds like I need more. How much should I be adding and how often - full dose each time I see stains after AA treatment? Should I buy sequestering test kit to take guesswork out like JimK? Once stabilized, what is the maintenance dose? By the way, how many quarts of HEDP are in a case?! Sounds like I am in same boat as JimK, and need a case or or two on hand for the near future. I also ordered a 4.5 Culator thinking the 1.0 was not enough - should I return it and continue with the 1.0? Not sure if it is working. Is still clean, but last time I cleaned basket, it seemed to have a clear gel on outside of the sack. Thanks for the help.

[PoolDoc]

Cookieman,

Last night, I dug out the old Monsanto Dequest 2010 -- HEDP -- technical literature I have, and have begun wading through it. Give me a day or two to re-read it, and think about the implications for pool use and dosing. One key element I'm not sure I'd ever noticed before is that high calcium reduces the effectiveness of HEDP. But test conditions were focused on boiler and cooling tower treatment, rather than pool use, so I need to check with Chem_Geek. And, I'm not sure he's ever seen this literature.

[JimK]

Thank you mbar, watermom, JimK and Ben for the helpful advice from experience. Please check to make sure my summary from all is accurate. Outside of bringing ph/chlorine levels up too high too fast, I did not add enough HEDP, and should not have used to trichor tabs ( in floatie and skimmer opposite of Culator)for chlorine source while using Culator. Stains have continued to darken while I am waiting on another batch of HEDP, Algeacide, and ascorbic acid, so, more questions: Are the skimmer tabs Ben refers to chlorine tabs or tabs for removing metals? The dosage on the KemTek HEDP for my pool is about 2 1/2 quarts per dose. I only ordered 2 doses, but sounds like I need more. How much should I be adding and how often - full dose each time I see stains after AA treatment? Should I buy sequestering test kit to take guesswork out like JimK? Once stabilized, what is the maintenance dose? By the way, how many quarts of HEDP are in a case?! Sounds like I am in same boat as JimK, and need a case or or two on hand for the near future. I also ordered a 4.5 Culator thinking the 1.0 was not enough - should I return it and continue with the 1.0? Not sure if it is working. Is still clean, but last time I cleaned basket, it seemed to have a clear gel on outside of the sack. Thanks for the help.

The Jack's Magic Purple Stuff has 12 quarts in a case. The maintenance dose for this product is 6 oz per 10k gal once a week. As I mentioned, since the bucket test Ben suggested was negative for metals, I've reduced the maintenance dose by half (3oz per 10k gal) and so far no staining has returned. I should be able to stop using it, but at least right now I feel better having that bit of insurance.

I noticed in the information posted about metal staining there is no mention of pool salt (high purity) being a possible source. Was I misinformed when I was told by my pool store that it could be a source of metals?