Hello, I am new to this site. I have a 24' Dough Boy above ground pool. Here is my problem. This past fall (after I closed up the pool) we had a storm come through and destroy the winter cover. I never replaced that cover (my mistake) and the pool ended up with lots of leaves and debris in it. When I went to get the pool ready this spring, the water was very greenish/brown. I got the water to be clear again, and got the leaves and debris out of it but now the liner is stained. I talked to the place I purchased the pool and showed them the pics. Their suggestion was to shock, shock, shock, and scrub with a brush. I have tried this and it is not working at all. Any suggestions on how to get the stains off the liner? Is there a good chemical I could use to get rid of these stains? The pictures I attached are after shocking and scrubbing.