Yellow stains on liner

AndyTN

Bronze Supporter
Mar 27, 2019
210
Memphis
So what is your plan to remove the iron? 4 hours with a little polyfill is not going to put a dent into it. You either need to do a water exchange of at least 50% right after AA has lifted the stains or invest time into letting the polyfill absorb the metals. If your fill water is going to have a decent amount of iron in it, you will just have to be patient with the polyfill and live with some stains for a while. You will need to get creative to pass as much water as possible through a large quantity of polyfill, which is why some people have used 5 gallon buckets.
 

cholmes28

Well-known member
Jun 9, 2014
179
Marietta, GA
I just got off the phone with a guy at Periodic Products, who seemed to understand completely the issue I am having with multiple AA treatments and stains coming back. He asked me if I had a lot of pine trees and whether pine needles collect in the pool. When I said I get a ton of needles in the pool, he is convinced I have iron bacteria. I bought the "eliminator kit" they sell (Iron Bacteria Eliminator Kit - CuLator Metal Eliminator and Stain Preventer), and he seemed pretty confident that this will fix the issue, so I am going to try it. He went through the entire chemistry explanation of this, and how the kit works, and it seemed to make sense to me, so it is worth a try. He is also throwing in some free products because I was willing to send a bunch of photos of the entire process.

I am going to replace the sand in my filter this weekend, because it is 10 yrs old, and while this is not likely to have anything to do with the metal issue, I have been suspecting there are issues with my water filtering for some time, so now seems like a good time to do this. Then when my kit arrives, I am going to give it a shot. I will let you know the results.
 

AndyTN

Bronze Supporter
Mar 27, 2019
210
Memphis
I bought the "eliminator kit" they sell
That kit has the products you have already tried, correct? The only exception is their algaecide contains copper. The CuLator packs work to remove metals over time but didn't you already buy one of these?

He asked me if I had a lot of pine trees and whether pine needles collect in the pool. When I said I get a ton of needles in the pool, he is convinced I have iron bacteria.
I have a lot of oak trees dumping leaves and Crud into my pool, especially in April at bloom. These cause tannin stains which can look similar to iron stains and chlorine eliminates them over several weeks. I have never heard of "iron bacteria" but I know chlorine kills bacteria and doesn't kill iron.
 
  • Like
Reactions: Texas Splash

cholmes28

Well-known member
Jun 9, 2014
179
Marietta, GA
Well after spending $500 on multiple AA treatments over the past month, I figured trying their "kit" was worth a try. He seemed pretty convinced that my issue was this iron bacteria, and said it was fairly new, but starting to get more attention. I need to raise FC to 10 during their process, which is opposite of the AA treatment. My kit gets here on Sat, and I will report back the results.

Side note, I changed my filter sand yesterday - what a pain that was. The process is simple, but getting all the wet sand out, and then the bags of sand I bought were a bit moist, so getting it in the filter was tricky. Took me a good couple hours.
 

AndyTN

Bronze Supporter
Mar 27, 2019
210
Memphis
Remember what I mentioned about the plumbing having iron stains which can be released into the pool during AA? I am dealing with a small leak and had to drain the water down below the returns. This is what the inside of my plumbing looks like. Once you get to the point of widespread iron staining, it will take years to eradicate, which has been my experience. Good luck and don't lose patience.

1589558770044.png
 

cholmes28

Well-known member
Jun 9, 2014
179
Marietta, GA
Just to give an update. My Iron Bacteria Eliminator Kit arrived Saturday, and I followed the directions precisely. Their process involved adding the copper algicide, followed by the sequestrant, raise FC to 20, add CuLATOR 4.0 packet to pump basket (this is to remove the copper from the algicide). Run pump continuously for 24 hours, test/maintain FC qt 12.5 for 48 hours. The first night I lost 17.5 FC in 15 hours (no sunlight), day 2, I lost 3 FC in 15 hours (no sunlight), day 3 I lost 2 FC. The staining was still there. I called and spoke to their "lead chemist" for a good 30 minutes, who gave me a college chemistry lesson on what was happening, but I cannot tell you here what exactly was said. The nut of it, was that when you have iron bacteria in the water, you are dealing with organic matter that needs to be killed before an AA treatment will be effective. He said that without killing this bacteria first, all the AA does is change the properties of the iron on the pool bottom (staining) so that it is clear (which is why it appears to be gone), but it doesn't actually lift the stain. That is the reason that when the stains come back, they reappear in the EXACT same place - they never actually lifted. He said that the presence of the organic iron bacteria was evident because the first overnight FC loss was so high. Now the process he said was to let the FC drop to 0, add the AA, followed by a sequestrant. What he said made a lot of sense as he explained it (especially the part about the staining returning to the exact same spot), but the proof will be in the pudding. Will report back with results.
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Well, I have to say, I am not very optimistic about the information from that company. In fact, some of it seems quite disturbing to me. What do you think @JoyfulNoise? For example, why sell a product containing copper, only to use a CuLATOR to remove it? Iron bacteria? I think it's common knowledge that iron is either in a precipitating stage (visible in water form or stains) or in soluble form (invisible and contained within the H20). I'm a bit skeptical about it all. I know you must be frustrated having dealt with this since opening, but I hate to see you spend money and time if it's not necessary. When all is said & done, I think fresh water (if possible) will be your best and most reliable solution. But as you said ....... we'll see and watch for your next report. Have a nice day.
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
16,606
Tucson, AZ
Honestly, if I'm being charitable and kind in my technical opinion of Periodic Products, I believe most of what they sell is junk and about one degree removed from snake-oil....

And as far as iron-bacteria goes, it is exceedingly rare to have any appreciable growth of iron bacteria in pool water unless the pool is a complete green swamp. Iron-bacteria is highly susceptible to chlorine sanitation; in fact, chlorine is injected into water wells to kill iron bacteria. Iron bacteria is found mostly in well water because deep wells have almost no dissolved oxygen in it and, because the bacteria needs an electron transport system to power cellular life processes, the redox reaction between Fe2+/Fe3+ is used. It's an evolutionary adaptation that occurs when bacteria live in extreme environments similar to how bacteria that colonize deep ocean geothermal vents live without any sunlight or oxygen by exploiting the redox reaction of sulfur and hydrogen sulfide. So the notion that anyone would have iron bacteria in a clear swimming pool with a detectable level of chlorine in it is laughable.

As for the CuLator stuff, well, until I see actual proof written up in a peer-reviewed journal or tested independently by a scientific lab, the concept is also highly suspect. It's basically a bag of ion exchange resin that you throw into your skimmer or pump basket. So the expectation is that this ion exchange resin is going to "absorb" all the metals in your pool water?? How exactly? Most of the water flowing through the plumbing will flow around the bag, not through it. So what...are they counting on diffusion of the metal ions into the resin?? Natural diffusion processes are extremely slow and, once the surface of the resin is fully loaded, diffusion into the bulk of the resin bag will be even slower. So how is this thing actually supposed to absorb anything from the water when 99% of the water flows around it at high velocity?? It simply makes no sense from an engineering or hydraulics perspective. That too coupled with the fact that most ion exchange resins are NOT metal specific...any divalent metal (Cu, Ni, Fe....calcium, magnesium, etc) will be captured by the ion exchange resin. The calcium levels in pool water are several hundred times higher than any metal concentration, so how exactly does this resin bag get loaded up with only one specific metal ion??

I'm not trying to make anyone feel bad, but these products are akin to snake oil at best. And, as Pat said, they just sold you an algaecide that adds copper to the water and now you have to get it out somehow (and I don't think the CuLator is going to help).

My best guess is (and I haven't read all 61 posts) that you simply have a lot of dissolved iron in your water and possible tannins from all of the pine needles. You live in Georgia which is an area of the country notorious for well water that has lots of iron it from the heavy clay soils that are rich in iron compounds as well as the larges amounts of decaying organic matter that acidifies soil and drives the iron into the well water and surface water. The stains keep coming back because as the chlorine and pH increase in your pool water, the iron is simply not stable and comes out of solution. Why does it always show up at the same spot, well, that's actually fairly common. Unlike a plaster surface which tends to develop scale, metal does not like to scale out onto vinyl surfaces. So there is something about those areas of the vinyl that allow for the scaling of metal to happen more quickly and easily than other areas. Typically surface roughness will enhance scale formation and so the vinyl may be slightly more rough in those areas (imperceptibly so to hands or eyes) and so those are the first areas where scale will form. As @AndyTN showed, PVC surfaces quickly become brown with iron because they are fairly rough on a microscopic scale.

If you cannot fill your pool with metal free water, then you have to either try to precipitate as much of it as you can in your filter or remove it with hose-end filters on the fill line. You will need to keep your pH on the low side (7.2-7.4) and use sequestrants to try to hold the iron in solution. Short of having an RO filtration company come out and filter your entire pool volume, metal scale is not going to be easily solved. I do feel bad for you as it is an annoying problem to have but, luckily, iron scale is just an aesthetic issue and not a sanitation problem.

Good luck to you.
 
  • Like
Reactions: Texas Splash

cholmes28

Well-known member
Jun 9, 2014
179
Marietta, GA
Wow, thanks for the chemistry lesson. I too am suspect about the whole kit they sold me, and what their "chemist" told me seemed to make sense, but so does you explanation, which I am much more inclined to believe yours than his. I followed what he said, and just began what will be my 3rd AA treatment. Staining was gone after about 45mins of circulating the AA. I just added the Metal-Free, and will wait 24hours and then slowly rain FC, while keeping pH around 7.2. I am not very confident this will work, and am planning to see the staining come back in less than a week. Argh! If it does, I am going to have to do the water exchange 1/3 at a time, but the staining will come back while I am doing this, so do I just wait until the last 1/3rd, and then do another AA treatment to remove the staining or what?

One thing I read on some other forums was that people seemed to have better luck keeping the staining off the surface by increasing their CYA to 50. Mine is about 35 now. Is there any science that would support this theory?
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
16,606
Tucson, AZ
One thing I read on some other forums was that people seemed to have better luck keeping the staining off the surface by increasing their CYA to 50. Mine is about 35 now. Is there any science that would support this theory?
Increasing CYA while hold FC constant decreases the amount of hypochlorous acid (HOCl) in water. HOCl is the primary oxidizer in pool water and so, if you lower it's concentration, you lower the ORP (oxidation/reduction potential) of water. The scaling of iron (Fe2+ oxidizing to Fe3+ and then forming insoluble iron oxide, aka, rust) is going to be directly related to the amount of oxidant in the water. But remember, if you operate at a lower FC/CYA ratio, then you are more susceptible to algae.

One thing you could do is keep your pH on the low side (7.2-7.5) and stay at the low end of the FC/CYA ratio. However, I would suggest you test for phosphates and remove them (reduce them to zero) and then also use an algaecide like polyquat-60 to help keep the potential for algae growth minimized. If you use a sequestrant that is based on HEDP (phosphonates), then I wouldn't bother with phosphate removal as the sequestrants oxidize over time and add phosphates to the water. However, if you are going to try to operate without using sequestrants, then it makes sense to remove as much of the phosphates as possible.
 

cholmes28

Well-known member
Jun 9, 2014
179
Marietta, GA
Joyful - I don't exactly follow your suggestion, and whether you are talking about doing this now, or if the stains come back or what. I am 3 hours into the AA treatment, and just waiting for a day or so before starting to raise FC slowly to flush out all the AA. Unless the Periodic treatment is a magic pill, I suspect I will start to see stains return as soon as I start adding chlorine. Perhaps I added too fast the last times. I shot for trying to maintain FC of 2.0, and tested every few hours, and added whatever was needed to raise FC to 2.0. In the beginning the AA was eating it up fast, but after a day 2, I was only losing the normal amount per day, so at that point, I brought it up to the target, which at CYA of 35 would be 5-6. Was this too fast?

Regarding the CYA, I understand the relationship between CYA and FC, so If I were to increase CYA, then I would also increase the FC based on the TFP chart. I guess what I am asking is whether raising CYA to 50, and increasing my target FC to 6-8, would help with my issue?

Then you talk about keeping the pH 7.2-7.5, (which is where I always try to keep it) and staying at the low end of the FC/CYA chart - by this do you mean where I am at now (CYA 35), or lower? And when you say use an algicide, do you mean as a maintenance dose, or as another treatment if the stains come back?

Also the This is the first time that I have heard someone talk about phosphates as not being snake oil designed for pool stores to sell more chemicals. Mine are high, as are my total dissolved solids but I never pay attention to that.

Sorry for the long post, but I am just a bit confused as to exactly what to try and when regarding your last post.
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
16,606
Tucson, AZ
Sorry for not being clear so let me back up bit and add more detail.

First, if you follow the FC/CYA ratio chart on TFP, there is no difference in using a CYA of 30ppm with an FC target of 4-6 or a CYA of 50ppm and an FC target of 6-8. In both the cases you have roughly the same amount of hypochlorous acid (active chlorine) in the water and it is the hypochlorous acid that drives the oxidation of iron and causes stains. What I was suggesting was that instead of using the target values, you use the Minimum value on the chart and try to maintain that as rigorously as possible. With manual bleach additions, it's difficult to do that but if you had an SWG or Stenner liquid chlorine pump, it might be easier. Honestly, a puck floater and periodic water draining would probably work in your case since the puck floater would act as slow, constant source of chlorine for the times when you're not able to babysit the pool.

Second, if you were to maintain your FC at the low end of the chart (CYA of 30ppm and FC no higher than 2-3ppm), then you would absolutely need some insurance to protect you against algae because, if you get an algae bloom then you have to SLAM the pool and SLAM'ing the pool will cause stains to return. So you want to avoid high chlorine levels at all costs. The only insurance against algae that is reasonable to use is an initial treatment dose of polyquat-60 and then maintenance doses thereafter. The PQ-60 can't fix an algae bloom but it can make algae harder to get started. Adding borates is another option as boron is a natural algaestatic compound (make it harder for algae to get foothold).

Finally with regard to phosphates - yes, it is often said on TFP that phosphates are snake-oil but that is gross oversimplification of the issue. The good-natured intent of telling people to ignore phosphates is to keep them from getting snookered by the pool store into buying chemicals that they may or may not need and therefore waste money. But phosphate removal is a very sound chemical principal in water management technology. Phosphates are a nutrient that all life needs in order to grow. Without phosphates, everything on planet Earth would die...that is a scientific fact. Algae ABSOLUTELY needs phosphates in order to grow - in zero phosphate water, no algae can grow and it would take both a large inoculation of algae as well as a load of nutrients to get a healthy algae bloom to start. Since removing phosphates from water is chemically very easy to do, phosphate removal finds many applications in water shaping (drinking water production, wastewater management, cooling tower and boiler water conditioning, etc). In your specific situation, removing phosphates from your pool water would be considered as helpful as adding borates or polyquat-60, that is, lowering phosphate levels gives you some insurance (wiggle room) against an algae bloom taking off. Since your staining is driven by high FC and pH, keeping the FC low helps to keep stains away. But, in order to live with your pool at low FC levels, you absolutely have to have some protection against algae and those treatments can help. That's all I meant when I suggested looking at your phosphate levels.

With respect to your AA treatment, you don't want to linger too long with AA in the water and slowly raising the FC. I agree that you need to creep up on the FC target you're shooting for, but it shouldn't take days to do that. What you want to do is add chlorine, brush the pool, give it 10-15mins of circulation time, then retest. If your FC is still zero, then add more chlorine, rebrush the pool, let it circulate and retest. Keep repeating that until you start to see the FC level holding. Then bring it up to your minimum value and keep testing periodically to see how well it is holding. Leaving the water in a twilight-state between AA and chlorine is just asking for algae to get a hold. I know it's tedious and time consuming to constantly have to add, brush, test, etc, but you really want to get FC in the water in a short time because algae only needs a few hours at most to double their colony size...it grows fast.
 

duraleigh

Admin
Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
33,376
Sebring, Florida
+1 what JamesW said. Chlorine is not a source for iron.
but I am going back to pool store for another CYA test, since they now do it computerized, so not as subjective.
Pool store testing is totally unreliable.....the computer only hinders the accuracy.....it doesn't help.

With 50+ inches of rainfall where you live (that basically replaces your entire pool, I would quit the band-aid AA treatments as well. I would divert roof gutter rainwater into your pool. It is iron free and your pool will be iron-free before you know it.

It might take some time to set up but your iron issues will be over.
 

cholmes28

Well-known member
Jun 9, 2014
179
Marietta, GA
Awesome, thanks for clarifying Joyful. So the summary of all this is:

Finish AA treatment, but letting metal-free circulate in pool for no more than 24 hours, then bring pH to 7.2, and TA back to normal (80?), then do the add chlorine, brush, retest, add, brush, etc until FC holds. Then...

Keep CYA where it is, and shoot for a target FC of 2-3 (this will be hard b/c I lose about 1.5 per day, which if I add at night, by the time I get home from work, it could be down to 1 or 1.5)

Add phos-Free to get phosphates down to zero

Add PQ-60, and plan on adding maintenance doses monthly (that is going to get expensive)

I am used to getting 2 mustard algae blooms per season, and come to think of it, I never got algae when I used to pay attention to lowering phosphates, so maybe that contributed to me getting the blooms when my FC levels dropped a bit because I forgot to add chlorine one or two days. As long as I am diligent about keeping FC at no higher than 3, pH 7.2, and add maintenance doses of PQ-60, then hopefully my stains do not return and I can enjoy my pool!
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
16,606
Tucson, AZ
Does Phos-free work for you? One thing I don’t like about it is that it is fairly weak in its active ingredient, expensive, and they add lots of other stuff to it like clarifiers. That might work in your case because you have a sand filter but for me, I have a DE filter so I use a commercial grade phosphate remover that is more concentrated and has no additive. That said, if you know how to use PhosFree and it works for you, then it’s fine.
 

cholmes28

Well-known member
Jun 9, 2014
179
Marietta, GA
The Seaklear is likely a much better product but not sure that it is less expensive than Phosfree. Dosage to remove 3000 is 32oz Seaklear vs 14oz phosfree and the price of a qt of Seaklear is about same as 2 liters of phosfree. I bought a qt of Seaklear for initial dose then may try phosfree for maintenance doses. If that doesn’t work will have to go back to Seaklear.

You mentioned using pucks in a floater to help keep FC More consistent at the lower levels What type of pucks would you recommend?
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
16,606
Tucson, AZ
Not sure what you’re looking at but PhosFree is a lot less concentrated. A quart (32oz) is SeaKlear in your 27,000 gallon pool will remove about 3000ppb phosphates. Based on the dosing chart below from the Natural Chemistry website, it would require 480oz, or 3.75 gallons, of PhosFree to achieve the same results.

Dosage Chart
Dose per 10,000 gallons (38,000L)

Phosphate LevelPHOSfree Dosage
300ppb or less0.5L or 16oz
600ppb1L or 32oz
900ppb1.5L or 48oz
1200ppb2L or 67.6oz

This why I don’t recommend using PhosFree, it’s generally a lot more expensive.

As for pucks, I was talking about trichlor pucks. 99% trichlor, no additives or anything. You can usually get them in a pool store. Costco’s and Walmart’s tend to sell the Clorox brand tabs that are “multipurpose” tablets and have lots of extra chemicals in them like copper and baking soda. You want to stay away from stuff like that.
 

AndyTN

Bronze Supporter
Mar 27, 2019
210
Memphis
While I am not going to be able to explain all the chemistry like you all can, where is the step for removing the iron? I know I personally wouldn't be able to sustain the precise chemical levels discussed here and the iron still remains for potential staining. This will take time but shouldn't a lot of the iron be absorbed over a few weeks with the FC causing the iron to precipitate to the polyfill strands? Isn't that the science behind the polyfill? The tiny strands create more surface area to precipitate and will have much more water flow than the rest of the pool surfaces?

Even if the incoming water is going to have some iron in it, wouldn't it still have a lot less iron than the current water in the pool? A water exchange immediately after AA treatment seems to be a lot less expensive than all these chemicals. Diluting the iron in the pool will also require less sequestrant and polyfill to get the job done. Wouldn't the phosphates also be diluted with the incoming tap water?

It just seems like we are getting too technical here with chemicals and are getting away from the basics. Thoughts?