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.
Citric acid for swimming pools.
4 1 out of 5 stars 105.
It does not harm a pool to have such a thin layer removed it simply clears away the stain.
After 12 hours brush and circulate.
I cover using bulk ascorbic acid and also using natural chemistry stain free which is citric acid.
Be sure ph is low and after cleaning return return water to normal chemical levels.
Ascorbic acid treatment this is how you use a large amount of ascorbic acid to treat staining in your entire pool.
Bosh chemical vanish pool spa stain remover 2lbs natural safe citrus based works excellent on vinyl fiberglass and metals removes rust and other tough stains.
Stainfree is ideal for treating staining on all pool surfaces and is compatible with all sanitizing systems.
This is a good treatment if your pool has a lot of staining and the spot cleaning is not an option.
Citric acid removes the stained area of a pool when applied by eating away the top layer of the pool s surface.
For citric acid 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.