Ultraviolet (UV) lamps designed for pools can neutralize most germs. They cannot keep a pool safe on their own. However, they will let you reduce the amount of free available chlorine (FAC) as low as 1ppm, or even lower under some regional laws.They can also break down some of the irritating or dangerous substances that show up in a chlorinated pool. Finally, although not normally used for this purpose, some types may break down existing high levels of chlorine.


Local health codes may have different requirements.
 A "MP" UV lamp is a versatile option with the following benefits:


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.
 This type of lamp, often called a purifier, has excellent disinfecting ability, though you will still need to use (reduced) amounts of chlorine.This may make it an attractive option for public pools.


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.
 There are a few other kinds of UV lamps, although they are less common. Here's some information to help you figure out what each product does:


"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).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.
 Hiring a professional to install the UV system is recommended. Once installed according to specifications, very little maintenance is required. Continue to test your pool for chlorine as usual, keeping it at 1ppm or another low level as recommended by your product or local law.
Understand UV disinfection.
Try a Medium Pressure UV lamp.
Consider a Low Pressure UV lamp.
Evaluate other types.
Test the pool after installation.
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