There are three ways to remove pool plaster stains;

Silky Terrier Dog Breed Playing Aro... Silky Terrier Dog Breed Playing Around

The first step is to connect an emery stone to the base of your swimming pool cleansing pole and rub the discoloration away. Despite the fact that this technique is the fastest and most straightforward, it may not be effective, even with a great deal of effort. In order to remove a stain, it is necessary to send a considerable level of force down the flexing pole. This procedure also has the disadvantage of gouging the plaster, which can result in a noticeable mark after the stain has been cleaned.

The second way is a serviceman’s trick that has been brought down. Shut off your motor and wait for the water to stop moving before turning it back on. Pour a little amount of granular chlorine (calcium hypochlorite) over the stains and allow it to sit for a few minutes. Just give it a few hours, and the color should be completely eliminated. Keep in mind that this procedure has the potential to create a stain on its own in a few specific conditions. In the event that you have a large number of stains, start with one location and see how it performs before putting chlorine on all of them. When using this procedure, if you are having difficulty keeping the chlorine on the stain due to the fact that it is on a slope, you might try another version. Fill a nylon pantyhose leg with approximately a quarter to a half pound of chlorine and set it aside. Afterwards, you can secure the hose with a string at the top and slowly lower till the chlorine is directly on top of the stain.  Do not immerse or remove chlorine-contaminated hosiery from the pool. When granular chlorine (calcium hypochlorite) comes into touch with even little amounts of water, it can become explosive and flammable, according to the manufacturer. Once the chlorine has been dissolved, it should be left in the water till it has completely dissolved.

The most effective method of stain removal from a plastered pool is to dive in. (A good alternative on hot days!) You’ll need wet/dry sandpaper from the home improvement store (a commenter suggests Scotch Brite). It also helps to wear a mask. Sand the stain off using sandpaper. This procedure creates a good surface and far less visible plaster. Do not use a power sander.