Yellow line around pool, just above water line?

[flyboy320]

Wondering what may cause this? My numbers are right where they should be. It's just around the water line, and slightly above it. I have tried magic eraser, vinyl cleaner (it contains enzymes), pure chlorine, and diluted muric acid, none of which seems to remove this. Is there anything else I can try?

The liner is one year old and I also added borates this year.

My next step is to try a vitamin C tab on the stain.

 

[zea3]

Does it wipe off and come back or does nothing budge it?

 

[flyboy320]

Does it wipe off and come back or does nothing budge it?

Doesn't budge

I think it's slowly getting worse over the summer, but it's hard to tell as it's not really noticeable yet. It's actually easier to see with my sunglasses on as it seems to bring out the yellow color more.

 

[zea3]

Oh, you took the picture down. I could see the yellowing you where talking about. I wonder if you raise or lower the water line if you can still see the yellowing. I honestly don't know what it could be. Try the vitamin C and let us know what happens.

 

[flyboy320]

I didn't think anyone else would be able to see it in the picture ......so I removed it. Ya it's not like someone painted a yellow line on the vinyl, just a faint haze of yellow.

 

[flyboy320]

Here are some pictures, although it's very hard to see the yellow line....

 

[zea3]

Have you had to shock or keep high chlorine levels? I just wonder if you drain the water down an inch or so if the yellow would extend deeper into the pool.

 

[flyboy320]

No the yellow stops just a hair under the water line. Never had to shock, highest chlorine levels I had was about 8 (CYA at 30), but that would have been only for a day at most since I test daily.

Does it look like the liner is fading from the sun (I know it's only a year old)?

 

[zea3]

I would think that if it was sun fading then the area above to just under the coping would be the same yellow, but it looks like about a 1" stripe of yellow just above the waterline. I'm stumped.