What do you think these marks are? video attached...

[supercanadian]

Hi Fellow TFP'ers!

I doubt anyone can identify this but I just noticed I have three or four marks like this at the vary bottom of my deep end. I can't scrubbed them out with a brush, but was able to remove most of the mark with a magic erasure sponge thing. Very odd marks, almost looks like a burn mark. The marks are spaced out over a few feet. They looked black at first and in the video below you can see the colour change after I scrubbed it a bit....can't get all the mark off. Can't feel anything on the liner itself.

It figures too its at the bottom of my 9.5ft deep end lol. A struggle to get down their and stay their to take any pics or anything.

At the seven second mark you can see it. Bonus points for water proof iphones lol.

 

[HermanTX]

Could be an abalone shell. Sometimes they are mixed with the plaster to give it some sparkle. I had a similar looking spot that came up about 1 year after my new plaster. The PB just dug it out with a knife and put some quick seal plaster on the small divot. You really cannot even see the mark.

 

[zea3]

Its a vinyl liner so can't dig it out. I would try crushing up some vitamin C tablets and laying them on the stain and see if it lifts. It could be something like a small piece of metal that was blown in and rusted there and was subsequently vacuumed up. Also if iron enriched fertilizer is used nearby, some of the granules may have blown into the pool. If the vitamin c doesn't work try laying a trichlor tablet on the stain. If that lifts it then the stain is probably tannins from leaves and will fade over time.

 

[HermanTX]

"Can't feel anything on the liner itself." Yep I missed this in the text. I looked at the signature and did not see neither plaster or vinyl. Thanks for catching that.

 

[supercanadian]

Thanks! ordered some vitamin C tablets this morning to give it a try. Funny enough we had some last week but my wife cleaned out the old meds.