My pool liner is stained brownish/black color on the bottom completely, except 1' all around the edge of the 24' diameter. Local pool stores advise me to put vitamin C in a sock & rub it out, to test to see if it comes off. It does with vigorous scrubbing. Black algae trmt. liquid
Pool stores sugguest this is the only way to remove the stain or spend money to try "First Aid" or find "Jack Magic".
Online research confirms this method is used, but a "sequestering agent" is also required - not sure what that is or is best.
Currently I have 1' of water in it, where it's easy for me to reach to scrub.
I keep the winter cover on to protect it from the sun. My pool is 20years old, the only problems I ever had was pink algae, which I could always get under control, and once needed to floc - (I pray I never need to do again). Have diatemaouse (sp?)filter & granulated chlorine, 3 solar panels
Besides replacing the liner, what is the most effective way resolve?