Odd brown spots on pool / plastic is pink

[Keri564]

I was not exactly sure where to post given I have two issues.

1) I clean my filter once a month. Last month (February) I noticed the pre pump filter and cartridge filter were pink. Filter is not OEM.
2) I immediately thought algea and looked around the pool noticing what appeared to be black algea in the shallow end by the steps but on the wall. It was noticed that more was in the deeper end almost as if the pool had been drained. Pool is just over 1 years old was never drained.
3) About 5 people gave their expert opinion including the pool builder who said it was black algea but wanted the plaster folks to take a look as I mentioned mottling. Here are their comments Black algea, fertilizer, metal in water, plaster issues… my friend in the business said stop until you have a diagnosis.
-A neighbor had sporatic black spots that the builder blow torched. I read that’s a bad treatment for plaster issues.

Here is what has been done.
1) A friend in the pool business said to try Jacks Magic the megenta stuff. I put in 6 oz per instructions but after a week with no change went to step 2.
2) After using a metal brush, rubbing the spot with a chlorine tablet then using 90% chlorine granular under the black areas(Trichloro-Traizinetruone), nothing changed. The weather changed and I jumped in with a mask. The spots are brown and appear to be part of the finish and isolated spots are throughout the pool. I tried to scrap some off test if it was algea.
3) The filter and pre-pump basket remained pink. I soaked them in dawn soap then in a chlorine water mix.

What makes it is is that some plastic parts turned pink but other plastic parts (I.e. the returns) are white.

I historically brought my water to be tested at a pool store but just received the 2006-C in as after reading the forum realized the chlorine test results were inaccurate after shocking. Plus a lot more reasons.

I did get two water tests at Leslie’s to test for metal. Note shock was done on 2/6/22, before I read about SLAM.
2/17/22
FC 13
PH 7.8
TA 70
Hardness 412
CYA 39
Iron 0
Copper 0.1
Phosphates 16
Salt 2559

2/23/22
FC 5.5
PH 7.3
TA 85
Hardness 366
CYA 41
Iron 0
Copper 0.2
Phosphates 38
Salt 3100

Note everyone agreed to wait until it warmed up to add CYA and Salt. I used a test strip on 2/28/22 all levels about the same as every week. I just added stabilizer, pool takes 2-3lbs of TA and 6-8 cups of muratic acid every week. Pool builder basically says I can never add enough acid. Funny that they aren’t concerned with CYA as SWG keeps chlorine steady - it disagrees with the forum’s recommendation.

I did have a pool service for 3-4 months that ended 10/31/21 as I have neck issues and couldn’t sweep. But I did sweep everyday the first 6 months then went weekly.

As I add water to the pool then test with the Taylor kit that literally just arrived I was hoping someone has seen this issue before.

Thank you,

Keri

 

[Texas Splash]

Welcome to TFP! Some of this may be difficult to determine since there's no telling what the previous techs added to the water during the pool service contract. Even though the store tests seem to rule-out iron, I would still rub a vitamin C table on some of that plastic anyways. Only takes a minute just to be sure. Wouldn't be the first time pool store testing (even for metals) was wrong. The 2nd test shows some copper which could make sense since too much copper can lead to very bad black spotting. Pool stores and services love to dump copper-based products into pools. So if the black spots can't be scraped off by your fingernail (algae), then it may be copper.

 

[Keri564]

Welcome to TFP! Some of this may be difficult to determine since there's no telling what the previous techs added to the water during the pool service contract. Even though the store tests seem to rule-out iron, I would still rub a vitamin C table on some of that plastic anyways. Only takes a minute just to be sure. Wouldn't be the first time pool store testing (even for metals) was wrong. The 2nd test shows some copper which could make sense since too much copper can lead to very bad black spotting. Pool stores and services love to dump copper-based products into pools. So if the black spots can't be scraped off by your fingernail (algae), then it may be copper.

Well. I didn’t have tablets so tried Emergen-c on the vacuum cap and it removed the pink. You can see I did the lid and the bottom left half. Not sure where Iron would get in the pool I’m using county water (or rain). I’m hoping I don’t have to run Emergency-c throughout the pool

I’ll probably need to buy tablets to test the brown spots in the pool but they seem like the pebbles in the plaster lost their color. Hopefully I don’t have an iron and copper issue.

Appreciate all your assistance

 

[Texas Splash]

Yeah, sometimes it's hard to know. Municipalities get their water from wells, aquifers, etc, so it's never guaranteed you won't have iron. Annual water reports "should" disclose such metals, but you never know. At least you now part of the equation. The black spots may not be iron. If they don't scrape off with a fingernail (algae), they may be copper. You can test one of those with some acid - maybe some dry acid in a thin sock if you have any.

 

[Keri564]

They don’t scrape off.

I put muratic acid down a pipe to them. Nothing changed. And they look brown under water with a mask on. I’ll update after I rub vitamin C on them.

I read the post about ascorbic acid treatment. I also saw posts about filtering via poly fill. I don’t want to get ahead of myself but have a start.

Thank you again

Hope my signature is showing

 

[Keri564]

The vitamin C worked on the line near the stairs but some blacks spots were not affected. I’m wondering if they are copper or fertilizer spots.

Reading through the forum I could not locate an area of recommendation when treating multiple metals say copper and iron (treat copper first then iron?). The forum states iron treatment could use citric acid but it’s not preferred and I read online that citric acid works on copper stains (no I don’t believe everything I read online or I would have bought some).

My question is- Does anyone know if citric acid is better if you think you have copper stains too? I can stick a pole down on the spots and pour muratic acid but dry acid sounds easier.

My neighbors say the water is horrible here and my friend who is a plumber referred me to a reputable water treatment company that is testing my water Tuesday. I expect them to try to sell me something but it might give some confidence in the cause of the iron is via fill water.

 

[Texas Splash]

Well, it's certainly possible you have more than one source of the staining. Copper is usually the most troublesome as the stains can really be embedded and quite hard to remove. Unless there was an unusual copper transfer from an item to the shell (maybe a big stretch), it's usually the overall copper content in the water itself. Copper could be introduced by an algaecide, over-the-counter pool products ("blue" or "yellow" something), or perhaps some old plumbing that has eroded. But if it's due to an elevated copper level, the only way to remove the copper is by exchanging some water.

Iron is usually the most straight-forward item to address. If it's just small, localized spots or stains, hand treatments are fine. Ascorbic Acid (AA) is generally the most common method to treat wide-spread iron staining. I'll put a link below. But remember that even with iron stain treatments, it's only "lifting" the stain from the surface and putting the iron into a water solution. From there, ideally you would also want to exchange some water with a cleaner (non-iron) source.

Fertilizer also pops-up from time to time. If you think it could be that, let us know and we'll dig-up some potential treatment ideas.

Ascorbic Acid Treatment - Further Reading

www.troublefreepool.com

 

[Keri564]

I called a water purification company, who doubted I’d have iron in the water but they tested two outlets. They found trace amounts of iron and recommended a water shield water softener.

I called the county water provider who indicated there are metals in the water and provided me with their quality report. They are also testing the water at my meter this week to see if it’s within acceptable levels.

I’ve been searching for hours and find conflicting information on if the water softener will eliminate all iron. The county didn’t think it would as “everyone is trying to sell you something.” They were surprised I’d see iron stains with a one year old pool.

I have also been searching for a filter to attach to a hose to remove ferrous iron but haven’t had much luck. My plan was to run the pool water through it via a sump pump and then use it to fill pool.

None of the products for treatment are carried locally so I’ll order from the links in the article. These folks were also curious about the fill water causing issues because they haven’t seen it in our town. They’ve seen it leak through the plaster but I don’t know how to tell if that’s occurring without eliminating the iron from the fill water. But then I’d still have issues determine the cause as I’d be using magic jacks to keep pool water iron off walls.

I’ll keep posting as I treat so maybe it helps someone. Just didn’t want this thread closed yet.

 

[Texas Splash]

It does sounds as though there is enough iron product in the water supply to eventually add-up in the pool. Over time, with large fills or periodic top-offs, the iron content grows. But at least you have an idea now and it sounds as if you are doing good research to try and manage it. If you have more questions later just let us know.

 

[Keri564]

Amazon delivered all of the products. The ascorbic acid was a lot cheaper on Amazon even though I got 4-5 times more than I needed but the other places had too high of shipping rates.

When I took ownership of the house for a few months I never checked the coverage of the sprinkler system that runs off Well water. One sprinkler pointed in the pool towards where the spots are in a line. Maybe they tested the sprinklers when the pool was empty but I definitely ran them when it was full. That is likely the source.

Posted picture of what I bought. The polyquat was the only difficult item to find on Amazon and I’m trying the culator out. I’ll probably wait a week until spring break is over to lower the chlorine and do the treatment. Then wait several weeks to ensure everything works out then do a full / partial drain.

Extra details you don’t need:

1) The county tested the water at my meter and at the fire hydrant and didn’t find iron. They found something I couldn’t hear in the voicemail and flushed it out the hydrant 2) the pool builder manager and plaster company came out with a guy that specialized in stains. They couldn’t figure out why the issue was horizontal and not vertical. No hydration or mottling but slight scale and definitely correct on iron.

Note about this forum: whether I was talking to the water company or the plaster folks having read this forum gave me the knowledge to challenge their assessment. It also provided me with tools to redirect conversations because I knew enough to be dangerous. For example, the county water folks said I’d see rust stains inside sinks and toilets and their process eliminates all iron to which I replied “unless it’s coming into my house in the ferrous state and not being oxidized into the ferric state until it builds up in the pool then gets hit by the chlorine,” to which they shockingly replied exactly. The plaster folks didn’t believe the line was iron either until I pointed out my skimmer basket was pink and they tested it.

 

[Texas Splash]

to which I replied “unless it’s coming into my house in the ferrous state and not being oxidized into the ferric state until it builds up in the pool then gets hit by the chlorine,” to which they shockingly replied exactly.

Ha ha.

 

[Keri564]

I started the vitamin c treatment last night as my chlorine went down faster than I anticipated.

Water chemistry before treatment
Ph 7.0
FC 0.6

The stains didn’t lift right away and the natural imperfections of the pool made it somewhat difficult to tell if it was working. When I added the ascorbic acid around the pool walls my steps turned brown, which went away but it made me nervous for the time.

I treated last night and let the pump run all night then added more ascorbic acid this morning and am now adding the magic jacks.

So I used about 2 pounds between the pool and bucket which is above the recommended treatment for the pool. The slight scale I have might have contributed to needing more acid (plus I did have some chlorine) and also the scaling could have made it more difficult to the results.

I used a 5 gallon bucket with ascorbic acid to try to get the iron off my nylon brush. That didn’t work I’ll buy a new brush. I’ll try it with a cartridge filter before putting in back in the system.

Wish list for wiki
-how does ascorbic acid get out of the water after treatment? Timeframe it’s active?
-use whole bottle of polyquat (like initial start up dose) I didn’t but wish I did. I don’t have any issues though.

Tonight I’ll start to rebalance per the wiki (Soda ash) then chlorine very slowly. I’ll end up draining the pool but want to give everything time to work to ensure the metals are in the water when I drain.

Then I’ll work on scale and see if the few black spots are ready just dark blue pebbles covered by some scale (dry muratic acid) One thing at a time!

 

[Keri564]

Okay so that iron line went away. I mentioned before that a large brown spot formed on the steps when I sprinkled the ascorbic acid near it. I quickly put the hose on it and it went away.

I noticed the deep end looked dark where the line ended that was my stain target. So I thought I might need more ascorbic acid. I dropped a vitamin C tablet and checked back in 15 minutes to see dark brown circle where the tablet was. I used the hose again it might have lightened it some. I read that I could double the dose of the purple stuff per the bottle. With the pump off I put most of it in the deep end then switched the pump on for the night.

Do I need to jump in and do the vitamin c test or is that spot an indicator of another problem? I was going to pour muratic acid if it was some how copper but posted here. I can get citric acid tomorrow morning instead of waiting on Amazon.

Interestingly my chemistry was not altered much

Ph still 7 (couldn’t find a way to test below 7)
TA down to 50

So I did not add soda ash yet as I have 3 water features that should raise ph.

 

[Texas Splash]

I would try teh acid test to see if it is copper.

 

[Keri564]

Is the dry acid Sodium Bisulfate? I only use liquid muratic acid.

The really dark part was lifted by this morning but you can tell that area is stained, which I never released as it’s always shady there.

Thank you!!!

 

[Texas Splash]

Is the dry acid Sodium Bisulfate?

Correct. While we generally recommend muriatic acid for everyday pH management, dry acid may be helpful to place in a thin sock or nylon for you to conduct the test.

 

[Keri564]

Appreciate it and everything else. I didn’t read that until I took these steps.

Ph 7.2 (no soda ash or ph up, crazy what the fountains do)

Suncoast identification kit (Magic Jacks rebranded for pinch a penny) no change to stain or dark spots that are actually dark blue pebbles. Rubbed vitamin c tablet on the spot too. Nothing.

I think the brownish color I saw during treatment was the iron going into the ferrous state and I have slight scaling. I guess it took more time for everything to work, I just assumed 30 minutes was the answer.

The spot is barely noticeable but also could be a poor plaster job (surprise). I’ll run the saturation index slightly negative as I read others have.

Wife is happy and wants me to stop. Good enough for me.

I know to raise chlorine slow to prevent iron going back on the wall. Besides what the wiki instructions explain and water exchange or drain let me know of anything else.

I hope my journey helps someone else!

 

[Texas Splash]

Wife is happy and wants me to stop. Good enough for me.