Staining - the mystery continues

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dayhiker

dayhiker

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LifeTime Supporter
Jun 6, 2008
304
Pell City, AL
I've had to deal with iron staining the past two years. In early March I did a citric acid treatment and have had the usual long road to get the chlorine level up and to hold. I've also had lots of trouble with getting green water due to adding chlorine too quickly, even if it was just a 16 oz cupful. Sequestrant gets it under control. This summer it's been much, much more sensitive to chlorine making me think the iron content was very high. I took a sample when I left home this morning around 7 and took it to a pool place around 12. They said the metals content was 0. Is it even possible for me to have orange staining that vit C gets rid of, and it not be iron? Same goes for the green pool with the addition of chlorine. The sequestrant makes it go away. I will take another sample to another pool place in the morning.

I did not have a chance to do a water test this morning. My office was taken out in the tornadoes in AL last week, so getting a new office established has things going crazy. My guess is that my FC is probably around 1 which needs to go up. CC could be present, but low if it's there. My TA is around 70. CYA is around 70. Salt is around 3200. pH is around 7.2 or so. Note that this green issue comes and goes regardless with whether my FC is 0 or 5.

Also, I think the iron is getting in from where my slab joint intersects the coping. In one place ants have a nest under the slab, so when there is a heavy rain, so some gets in the pool. Alabama red clay is red because of iron. I'm going to use a semi-rigid epoxy to seal all of these joints.

I'm just sort of at a loss after she said no iron or copper. After getting a second opinion, what would a next step be?
 
Many of the iron tests are unreliable. Everything you described suggests iron, I doubt it could be anything else.

Higher iron levels require the use of more sequestrant. If there is iron in your fill water, the iron level in the pool will go up any time you top off the pool after evaporation.
 
JasonLion said:
Many of the iron tests are unreliable. Everything you described suggests iron, I doubt it could be anything else.

Higher iron levels require the use of more sequestrant. If there is iron in your fill water, the iron level in the pool will go up any time you top off the pool after evaporation.
Click to expand...

I'm having to use 2qt any time I add bleach...even as little as 32 oz. I figured my levels were now sky high and was wondering if maybe a partial removal and replacement might be in order. Is there a way to reliably test the concentration in the pool and in the fill water?

Does what I described on the slab joints make sense? I can't think of another reason for the concentration to apparently increase. I am downwind of a pretty major power generating plant....who knows what in the air :)
 
I use the Taylor drop based tests for metals. They are better than what most pool stores use, but not perfect.

If a significant amount of iron was coming from the slab joints, I would expect a trail of stain from the slab joints into the water.

If you are having consistent problems with staining, try keeping your PH down around 7.2-7.4. Staining is much less common at low PH. Also try switching brands of sequestrant. Some are much better than others.

I wouldn't start replacing water until you get some more information.
 
I wish I had paid more attention to what she did.

Is K-1716, the correct kit? It looks like that is the only kit that tests iron only, the others on the Taylor test kit were pretty high end.

There's a Leslies in Birmingham, I wonder if maybe they use this drop kit for their testing. I think I'll give them a call. It would be nice to find a place that already used this test kit. I'll report back once I get an iron concentration confirmation.
 
I've kept my staining under control, but have had something else pop up. Last year I kept getting error codes on my flow sensor for my salt gen. I emailed back and forth with Jandy and it looked like it was cooked. The guy felt like the iron contributed to it shorting out. I bought a new one and it's been in use maybe a month now. Last weekend I got some Vit. C tablets to spot treat the skimmers and inlets, though, for the most part things look good (mention this in case that extra iron in the water is an issue). This morning, my solar gen. chirped at me and I got the same codes as last year when my flow sensor went bad. I cut off the pump (I had left it on overnight because my chlorine was low) and went to the office for a few hours. I come back, the timer has kicked it on and it's working great. In the mean time, I'm concerned about the iron. I take a sample to a different pool store and had the water tested. First off, wow at the difference in their numbers and mine. They said iron was 0. The person (the owner who does seem fairly knowledgeable) I talked with had never heard of using vit c. I said I had iron and could scrape the stain with the tab and it would come off. She also shot down my slab crack issue with dirt in the pool (I realize that's a stretch on my part) and suggested I bring tap water for comparison. I will do that.

Now to the parts I'm really curious about:
1. If my iron concentration is fairly high, is it plausible that it could cause a flow sensor to go bad?
2. If yes, could it cause it to go bad that quickly?
3. She informed me that metal out does actually take the metal out of the water and it does it by you cleaning your filter. She said for a cartridge to use muriatic acid.

Based on what I've read here over the last 2 years, #3 sounds like bunk. Cleaning the filter won't get the iron out and muriatic isn't good for cartridges. Am I correct on my understaning of those two points? I should have asked what method of testing she uses and will do that when I take the tap water.

Part of me wants to freak out about the flow sensor and make 1+1 = 2. The other part feels like I should go back in and check all of the contacts and clean them. I do know that I need to replace the electrical connector for the wires coming into the bottom of the box. A plastic washer has broken, so the connection dropped about 2" and therefore doesn't provide a seal on the bottom. I wonder if this is merely a humidity issue causing corrosion? On that some type of note, last year my polaris timer wasn't working, I took it all apart, tested everything, and then it worked. This year, it doesn't work. I did mess with it some but with no luck. I mention that to say that most of this stuff is fairly fragile on the electrical end and wonder if most of these issues aren't more likely to be contact/corrossion issues.

That was a long, rambling diatribe there, but I believe I hit all of the points.

Thanks for any advice anyone can offer.
 
Soaking the filter in acid is a very specialized thing that almost no one needs to do, but can be useful sometimes. Basically if you get a lot of calcium scaling on the cartridge, it needs to be throughly cleaned and then soaked in a diluted acid solution to remove the calcium.

Iron has no effect at all on most flow sensors, but I am not familiar with the exact technology used in the Jandy units, so not sure what kind of flow sensor they use or if it would be affected.

Sometimes, but not at all reliably, sequestrant will cause the metals to clump up into clumps large enough that they get filtered out. So, sometimes you get lucky, but usually it doesn't work.
 
Based on that, it sounds like my flow sensor issue is either the contact thing I mentioned, a huge coincidence if it is going bad, or something very strange. Does that sound reasonsible?

We talked about iron sources some. She mentioned fertiziler. I do have chemlawn come, but they don't get very close to the pools (30'+) and I've never had a phosphate issue. She mentioned the end of a hose left in the pool. I don't do that, but I think my hose is brass.

I won't worry about the acid treatment then.

Thanks a bunch.
 

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I read something the other day that said that there was enough copper in a penny to stain a whole pool which made me second guess that spot. The first time I opened the pool (spring 08) I found a roofing nail in teh bottom. Today I was cleaning up some stains on the main drain which made me wonder if there could be one under that drain cover. It looked like two screws on the top plate and then 4-6 at a lower level. I assume the top two screws turns a cover loose and then the 4-6 anchor it to a box in the ground?
 
dayhiker said:
I read something the other day that said that there was enough copper in a penny to stain a whole pool which made me second guess that spot.
Click to expand...
A penny weighs 2.5 grams. It is copper-plated zinc with 97.5% zinc and 2.5% copper. A 10,000 gallon pools is around 37,850 gallons so the copper penny would introduce (2.5 g)*(2.5%/100%)*(1000 mg/g)/(37850 liters) = 0.0017 mg/L. Even a pre-1982 penny that was 95% copper wouldn't be that much -- roughly 0.063 mg/L. So what you read is basically another one of these myths that pervade this industry.
 
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