We just bought a new house and lucky us it has a swimming pool! It is a beautiful pool but has yellow stains all over the concrete walls. I do not think it is algae as it is not slimy, does not scrape off or have any texture, and does not appear to affect the water at all. All chemical levels are right where they should be and the water is clear.
Is it just permanently stained? I am not sure how long it has been there and I am thinking maybe the past owners just never brushed it so it build up stains over the years.
Any advice on how to diminish these stains?