Ugly rust stains on the surface of your fiberglass swimming pool can distract from the aesthetic appeal. Mineral deposits and chemical breakdown of metals contribute to these unsightly spots. Stains of this nature present a bit of a challenge, but when geared with the proper equipment and correct techniques, any pool owner can effectively eliminate stains from her fiberglass swimming pool.
Apply a vitamin C tablet directly on the stain. If the stain is due to metal, it should lift up quickly. Scrub the affected area with a soft bristled brush to work out the stain.
Apply ascorbic acid powder to your pool filter, according to the manufacturer's specifications. This is helpful if several stains are spread across the entire pool.
Scrape a chlorine tablet over the stained area to bleach out the stain. Scrub the area with a soft bristled brush to aid in the stain removal.