Stubborn "bathtub ring" around vinyl liner

I have been a follower of the Pool Forum for several years now and appreciate all of the great information compiled here, thank you! I’ve usually been able to find answers to my questions/issues over the years by searching through the Forum. Somehow I cannot find my current problem addressed so I am posting for the first time – a newb.

I have a 24 ft. round AG pool with vinyl liner. I've had the pool for about 4 years now and noticed that over the past 2 years, it is developing a dark ring above the water line. We tried using some Soft Scrub but this was only very minimally effective. I’m a BBB’r so knew I might be risking water balance by using the Soft Scrub but fortunately it did not seem to have much negative affect on the 13,500 gallons of water. I have a couple of teenage daughters who like to have their friends over in the pool. They use tanning oil and my thought is that this ring is a result of their increased use of the pool and the tanning oil over the past few years. What is the best way to get rid of this ring and keep it away? Thanks for your help.

On concrete pools, you can scrub the tile line with baking soda on a sponge, and that works. On liner pools, it's my impression that the black ring tends to bond with the liner, and is harder (impossible?) to remove, but it won't hurt to try.

Someone else may have a better solution.

Try the baking soda. I have a liner pool and that is what I use. You know the kitchen sponges that have a sponge on one side and the other side is a little rougher? (Not TOO rough, though.) I put some baking soda on it and gently rub the waterline. Having said that, my pool doesn't have the oily ring that it seems yours does because we mostly swim in the evenings so sunscreen isn't needed. But, it won't hurt to try the baking soda and won't hurt the chemistry as long as you don't use buckets of it! :eek::eek:

Thanks. Guess I know what I'll be doing this weekend.

Yes, but you can do it from INSIDE the pool!

Of course from inside the pool! Just like when I vacuum. I am always in the pool when I vacuum except in the spring when I open the pool and the water is still too cold.

I've used a product from the dreaded pool store made for cleaning the wall, tile, vinyl, etc... that will not mess up your chemistry. If I remember correctly, it's some kind of mild acid ingredient and looks like pink dish-washing liquid, very thick. It does not foam and seems to dissipate rather quickly. I used it with the mildest scrubber pad (3m type) I could find (the white one-- don't use green, too rough, blue is also a bit rough). Anyway, it might be worth a try if the baking soda does not do the job.
It's mild enough that you don't need gloves or anything else special. I used it on the vinyl at the water line and on the white steps at the end of the pool successfully with no scratching of the surface. Of course, like any pool store stuff, it costs way too much.

Good luck.