Use a half a pound of vitamin c for every 10 000 gallons of water.
Citric acid wash for pools.
Wet the sides of the pool.
You will need to use 2 lb.
4 1 out of 5 stars 105.
Mix it gently with a mixing stick if you need to.
Fill the can with 1 gallon of water and then add 1 gallon of citric acid always in that order.
Pour water over any remaining.
An acid wash would likely remove it you can test by lowering the water level down below the first step and pouring a 50 50 acid water mixture from a flower watering can over the step scrubbing briefly and hosing off within 60 seconds.
Rinse out the bowl.
A citric acid wash is most effective on a swimming pool that has been cleaned with all debris removed after it is drained.
Pump the mixture into a bowl using a submersible pump.
When you get the ascorbic acid in the water you can turn on the pool pump and let the filters circulate the water for about a half hour.
In your five gallon bucket add one gallon of acid to one gallon of water never the other way around.
The acid wash is applied from a watering can used for flowers.
9 kg of soda.
If it works an acid wash would be a good next step.
For citric acid for pools.
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.
Spray down the sides of the pool and make sure the entire surface is wet.