As a general rule, free available chlorine (FAC) should be between 1 and 3 ppm. Total chlorine should be no more than 0. 2 ppm higher than FAC. Your local health codes may have different requirements. [3] X Research source If your pool also uses ozone or UV disinfection, FAC can be reduced as low as 0. 5 ppm.

To stop adding chlorine, turn off the chlorinator, chlorine feeder, or salt water chlorine generator; take the chlorine tablet out of the pool skimmer; or remove the chlorine floater. If you are not sure which system the pool uses, ask the manager or owner.

Ultraviolet lamps are not usually a good replacement for this step. See the UV method below for more information.

Do not swim if your pool test had additional unexpected results, such as the wrong pH or alkalinity. Do not swim if you smell a strong “chlorine” smell (and the chlorine test gave high results). This smell is actually from irritating substances called chloramines. [5] X Research source Chlorine affects the lungs. It is more dangerous in poorly ventilated areas, and if the swimmers have breathing problems. [6] X Research source

If you have a filter has a backwash option, this is the fastest way to (partially) drain your pool.

See Tips below for guidelines on other test results, such as pH or cyanuric acid. If your test results fall outside these guidelines and do not correct themselves soon, you may need to hire a professional.

Sodium thiosulfate is probably the most common chlorine neutralizer, but requires care when handling. Hydrogen peroxide is often the cheapest option, and breaks down into harmless substances. However, this is much less effective if your pool’s pH is below 7. 0. [7] X Research source

Read the product label carefully for safe handling instructions. Follow all recommendations for safety equipment, and review emergency protocols. Store pool chemicals in a well-ventilated storage area, away from sunlight, heat, and moisture. Do not store acids and chlorine near each other. Do not store dry chemicals next to or underneath liquids. Only have one chemical container open at a time. Close the container and return it to storage before opening another.

Generally, when adding sodium thiosulfate, allow for about 0. 5 ounces (15mL) per 1,000 gallons (3,800L) water. If you’re treating a public pool, go with a more accurate measurement. 2. 6 ounces (77mL) sodium thiosulfate will lower chlorine by 1 ppm in 10,000 gallons (37,900L) of water. [9] X Trustworthy Source State of Indiana Official site for state-approved sources related to life in Indiana, including laws, services, and culture Go to source A pool store employee or an online pool chlorine lowering calculator can help you with this formula.

If your circulation system is slower than average, you may have to wait longer for the neutralizer to take effect.

Local health codes may have different requirements.

This is the only common lamp that will break down a significant amount of existing chlorine. Even then, you’ll need a dose 10–20 times higher than the amount recommended for disinfection. This will probably require multiple lamps. This is the most effective lamp for breaking down chloramines, the substances usually responsible for stinging eyes, irritated skin, and “chlorine” smell. This lamp is fairly good at disinfecting, but not the best option.

These lamps also tend to be cheaper and longer-lasting than MP lamps. Advertisements may claim these lamps remove chloramines. This is partially true, but in practice they may or may not reduce the obvious signs, such as stinging eyes.

“Ultraviolet” actually includes a wide range of light with different effects. It is usually divided into UV-A (315–400nm), UV-B (280–315nm), and UV-C (100–280nm). [11] X Trustworthy Source World Health Organization Health information and news provided by the World Health Organization Go to source You should be able to find either the light type or a range of wavelengths (such as 245nm) for any product. Only UV-C light helps disinfect pools. Only UV-A light (including UV light from the sun) breaks down significant amounts of chlorine. Even then, it will take an intense amount of light. All three types help break down chloramines.

To keep the pool in good condition, vacuum it once a week. The plaster cannot tolerate a lot of dust. [12] X Research source Vacuuming helps to maintain the color of the pool. When you go for a vacation, the water may become Tahoe blue or gray. But when you vacuum it, it becomes blue once again. This method is not expensive. The reason is that most vacuums do not cost more than $200. [13] X Research source