Muriatic acid added to the pool water will not remove stains from Swimming Pools. Unless you do an acid wash. Something that should be left to an experienced pool tech. Purchase a good test kit that will measure chlorine, pH, alkalinity and conditioner. This test kit will, after the initial test for pH and with a further test, give you amounts of muriatic acid to add to your particular size, in gallons, pool.
K
Baking soda is the best way to remove acid stains from concrete. Dawn may remove grease stains from concrete. Vinegar is another great solvent for grease stains.
Sorry, battery acid stains are permanent. The acid will eat away the cloth.
washing up liquid is an alkali as it neautralises acids .
Oxalic acid (one teaspoon) to remove rust and iron stains
it contains citric acid
Drain pool and clean with muriatic acid
To remove phosphoric acid stains on black plastic, make up a paste of white vinegar and baking soda. Apply the paste to the stain and allow to sit for a few minutes, then rinse with warm water.
Use a 10% solution of pool acid and wash with water
Since you cannot remove the "stains" with the methods you have tried perhaps the stains are from too much acid or high acid levels. Are there also copper colored stains as well? Do you have a pool heater in the system? If so, then it is copper stains from an acidic pool water. The over acid conditions are stripping the copper from the heater copper tubing. k
Phosphoric acid will remove iron stains. Vinegar may also work. You need to keep the surface wet with the acid for it to have long enough to work. CLR also works. Wear rubber gloves and eye protection if you use phosphoric acid. Phosphoric acid is sometimes available at pool supply companies. Pool supply companies may have other suggestions. Janitorial and restaurant supply stores also will have some good cleaners for iron stains.
Oxalic or Muriatic Acid diluted with water will remove rust stains from a roof. Here in Tampa, Muriatic Acid is common, used for swimming pools. Diluted 1 part acid to 4 parts water, it will remove rust stains off a roof. Plain Vinegar is a mild acid, and should be tried first! You may have to apply several applications of it, but we here at Apple Roof Cleaning Tampa suggest you try it first ? More roof rust stain removal info may be had by going here http://roof-cleaning-institute.activeboard.com/
I was told to just super chlorinate the water. You may have to repeat with the super chlorination, but over time, stains should fade away.