Your best bet might be to empty the pool clean it out and start over.
Citric acid treatment for pools.
Citric acid is a gentler stain remover than muriatic acid another form of acid used to remove stains and resurface swimming pool interiors.
Keep in mind that ascorbic acid is best for treating iron stains while citric acid is best for treating copper stains.
Run your filter for at least 1 hour.
Depending on the pool size and stain size another method besides treating the whole pool with citric acid is to treat the stain directly that is fill a literal sock with citric acid and put it directly on the stain initially with circulation off.
I cover using bulk ascorbic acid and also using natural chemistry stain free which is citric acid.
For tough stains sprinkle ascorbic or citric acid directly onto the spot.
This is how you use a large amount of ascorbic acid to treat staining in your entire pool.
You might be able to filter it out over time but as long as you have both citric acid and calcium in the water more precipitates will form.
Treat large stains by adding ascorbic acid to the pool water by sprinkling it evenly over the surface of the water.
If you don t overcome it pretty quickly though you may need to shock the pool since keeping the chlorine at low levels for very long will allow algae to bloom.
After 12 hours brush and circulate.
Start by using a 1 2 pound of ascorbic acid per 10 000 gallons of water in the pool.
Citric acid removes the stained area of a pool when applied by eating away the top layer of the pool s surface.
Deactivate excess metals with a metal reducer like metal free or metal klear add a 1 2 pound of ascorbic acid per 10 000 gallons or water.
This is a good treatment if your pool has a lot of staining and the spot cleaning is not an option.
My pool has some staining on the steps and some of the walls.