brown stain on fiberglass pool

[aylad]

You can try a crushed up trichlor puck, or, depending on where it is, a magic eraser....if it's under the waterline, shocking the pool will sometimes remove it over time.

Janet

[thepoolman1]

One of the best products I have found to remove brown stains from a fiberglass pool is cal-hypo (calcium hypochlorite). If the stain is on the bottom, put enough in to cover the stain and let it sit. If on the walls, try to get a good amount on the floor just below it. Should be the answer.

If you decide to do this, be very careful to either buy a small amount and use it all, or store the product very carefully. DO NOT ever mix it with any other product other than in the pool itself and always add the chemicals at different times or as far away from each other as possible. I have been using this product for over 15 years in the business and these are not suggestions. It is a very good product, but you have to understand the proper use and be aware of the potential for problems.