Pool and spa: chlorine water treatment

Chlorine is the most common product used to treat water in swimming pools and spas. It is also the most economical treatment compared to salt and bromine. Its disinfectant property eliminates all micro-organisms in the water and it is an effective algicide. Are you unsure of what to use for your pool or spa? Read this article to find out.

Healthy and clear water. chlorine

Benefits of chlorine treatment

Chlorine treatment offers many advantages:

  • It is a powerful algaecide and disinfectant
  • It is very easy to use and convenient.
  • Chlorine is the most economical product.
  • It is sold everywhere (supermarkets, specialized stores,...)

Chlorine in all its forms

Pool and spa chlorine is available in several forms:

  • Chlorine in pebble: This is the most commonly used form. Simply slip a pebble into the skimmer of your pool or into a floating diffuser (for self-supporting/out-of-ground pools) and let it dissolve gradually. These chlorine pebbles are slow-acting and are used to keep the chlorine levels as they are. Smaller pebbles can be used for occasional chlorine shock actions.
  • Chlorine powder: dissolves quickly and is often used as a "shock treatment" restarting your pool or when the water is very dirty.
  • Liquid chlorine: is more difficult to dose and handle.

The different types of chlorine to disinfect your pond

You can find two types of chlorine in the market to treat your pool:

Unstalibized Chlorine. It has a strong disinfecting power, but it is not protected from UV rays. It is therefore destroyed in a few hours. It can be supplemented with a stabiliser. It is therefore used more by spa owners. Read more.

Stabilized chlorine contains a stabilising agent, cyanuric acid, which protects it from UV rays. It is the most commonly used form of chlorine for swimming pools because of its comfortable and complete use.

How to measure the chlorine level?

There are several types of chlorine: free chlorine, total chlorine and active chlorine. Not all of them are responsible or active in disinfection. That is why you have to be careful with the type of chlorine that your strips or devices measure in your pool. This can explain differences in results between different measuring solutions (strips, DPD tablets, connected probes).

Youtube video. All about chlorine. Ondilo
A chemistry expert explains the differences between the types of chlorine.