Insight to a puzzling occurrence.....

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weslynf

weslynf

0
May 27, 2016
5
Powder Springs GA
I have been a pool owner for only 5 years so and I stay on top of water chemistry and any problems that comes up I deal with them quickly. The last three years I have these black/dark20210806_194446.jpg spots come up on the liner. It only happens around this time of year but eventually they will disappear around January. You can't feel any difference on the liner where they are and it doesn't rub off. I have asked everyone I know around here about it and no one seems to have an answer to what it is. Here is the details of the pool itself:
23,000 gallon pool with spillover spa
Pentair SWG and sand filter
Pentair spa heater
vinyl liner

Can anyone identify what this might be?
 
Hi, and welcome to TFP! How have you been sanitizing your pool? Have you added any algaecides, if so what did you add?

Chris
 
Wes,
I see you've been a member for a long time. You are clearly not following TFP methods with Bio guard 60 and it's likely this or one of the other products you've used is the source of your problems. TFP methods will prevent situations like the one you have. Looks to me that you either have a metal stain from a previous algaecide or algae but I can't really tell without more information including:
  • a full set of test results from a recommended test kitRecommended Levels
  • vitamin c test on the spots
  • scrape some of the stain if possible and wipe between your fingers and tell us if it's green
  • tests for metals including copper and silver content in your water (likely due to other commercial products you have added)
We are here to help any pool owner but it's much easier if you follow our methods. We simply can't just guess what to do based on a photo. We need test results and then it's usually fairly straight-forward to figure out.

If it were me and I inherited your pool I would drain, clean refill and use TFP methods only from now on. But that's entirely your choice and what's good for you is your call. If you need more help with this approach we have tremendous experts to help you. If not, and you can post some tests results we'll still try to help.

Chris
 
What are all of the chemistry readings?

Why is the main drain grate purple?

Do you add copper algaecide to the water?

The stains might be coming from behind the liner.

Does the yard get really wet this time of year?
 
setsailsoon said:
Wes,
I see you've been a member for a long time. You are clearly not following TFP methods with Bio guard 60 and it's likely this or one of the other products you've used is the source of your problems. TFP methods will prevent situations like the one you have. Looks to me that you either have a metal stain from a previous algaecide or algae but I can't really tell without more information including:
  • a full set of test results from a recommended test kitRecommended Levels
  • vitamin c test on the spots
  • scrape some of the stain if possible and wipe between your fingers and tell us if it's green
  • tests for metals including copper and silver content in your water (likely due to other commercial products you have added)
We are here to help any pool owner but it's much easier if you follow our methods. We simply can't just guess what to do based on a photo. We need test results and then it's usually fairly straight-forward to figure out.

If it were me and I inherited your pool I would drain, clean refill and use TFP methods only from now on. But that's entirely your choice and what's good for you is your call. If you need more help with this approach we have tremendous experts to help you. If not, and you can post some tests results we'll still try to help.

Chris
Click to expand...
This is where I have a problem..... The recommended levels that you guys have are different than that of the manufacturer of my pool equipment, so what should I do? Which levels do I follow?

Clearly you did not read my post because I already said nothing rubs off or there is no difference in the feeling of the liner on the spot. I will get a water test today and post the results
 
JamesW said:
What are all of the chemistry readings?

Why is the main drain grate purple?

Do you add copper algaecide to the water?

The stains might be coming from behind the liner.

Does the yard get really wet this time of year?
Click to expand...
The main drain is/was grey

The stain coming from behind the liner is what I was thinking but the fact that it disappears later I felt ruled out that possibility

The part of the yard that is on that side of the pool is well drained so it actually should stay drier than any other part of the yard
 
I think that it is probably coming from behind the liner.

You probably won't be able to do anything until you replace the liner and you can treat the spot.

Check the ground water level to see how far down it is.
 
weslynf said:
This is where I have a problem..... The recommended levels that you guys have are different than that of the manufacturer of my pool equipment, so what should I do? Which levels do I follow?

Clearly you did not read my post because I already said nothing rubs off or there is no difference in the feeling of the liner on the spot. I will get a water test today and post the results
Click to expand...
Wes,

OK I get your dilemma and sorry, I did read your post thoroughly just was making absolutely sure since it helps to narrow the cause. I think after 5 years I would try proven methods but you that's a personal preference of mine and it's easy to see your logic/preferences. Looks to me that one of the big spots is actually on the drain cover. You've now got experts engaged that know way more about pools like your vinyl liner than I do so I'll bow out.

Good luck to you.

Chris
 

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What are the black stains on the floor of my liner and how do I get rid of them? | McEwen Industries

If you have black or grey cloud-like stains on the floor of your in-ground vinyl liner, they are most likely caused by bacteria that is living in the ground under your pool. Bacteria sometimes show up years after a pool has been installed. We think the bacteria can be washed into your pool area by
www.mcewenindustries.com www.mcewenindustries.com

 
Last edited:
+1. Had a friend who’s liner floated during a Tropical storm. The ground water level stayed high for a while and they were left with algae under the liner which they could see through it. It remained until they got sick of it and replaced the liner. I imagine it’s only a matter of time for them until it happens again.
 
Those stains being wet behind the liner will dry up as you say come fall here in Georgia. It gets dry and hot.... things dry out. I lose more pool water to evaporation during early fall (Indian Summer) than any other time of the year.
 
Pics of my own liner crumpled up while removing the pool. The ground and liner had a few days to be dried out at the time of the pics, but when I first ripped the liner out it was half an inch thick on both and the darkest hunter green shade. It was a thick liner and even though it was bleached white from the previous owners love of granular shock, it didn’t show through 3BD3EFF4-4F95-46AD-AC2E-EECE800A7391.jpegBF79658D-857C-43D6-929B-329DD25E0E20.jpeg
 
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