liner stain remover

[victoreh]

Hello,
I opened my pool this past memorial day and have enjoyed the pool in northern NJ this summer - we had some incredibly hot days.
Unfortunately, I never opened the pool last year and my liner is stained. I've shocked and brushed but the stains will not lighten or remove.
I need advice to try to clean the stains as an alternative to replacing the liner next year. I will close the pool before the end of this month, likely before Sept 17 if I can get everything in order - ie; remove the stains before covering.
Thanks in advance.

 

[PoolStored]

If they are organic stains from algae, raise and maintain your FC between 60% and 100% of SLAM level FC. Hold it there until the stains lift.

For example, if your CYA is 40, SLAM FC is 16. Maintain FC between 10 and 16.