
How do I get rid of this stain from my Above Ground pool?
I have tried everything but cant get rid of this stain. After removing my above ground pool I noticed this outline. I want to say maybe the algae or pool chemicals caused this over the 3 months the pool has been up but I am not 100% sure. I have purchased a gas pressure washer and used Zep and other things like liquid chloride diluted to 5% and I cant seem to clean this up. Any tips are welcome.