why will chlorine react in a water that is very clear but chemical has iron content?which turns it brownish.and what is the fastest why to remedy the water?

Perhaps I have deciphered the question properly but I'm not sure.

Water that looks clear and colorless but has iron content is turned a brownish color when Cl2 is added because the Cl2 oxidizes the iron (mostly there as ferrous or other compounds) to ferric and that is brownish in color.

And I don't know "why" to remedy the water; I don't even know what you are asking.

Chlorine reacts with iron in water, which can lead to the formation of a brownish color or staining. This is because chlorine acts as an oxidizing agent, and it can oxidize the iron present in water to form iron oxide compounds, commonly known as rust.

To remedy the water and remove the brownish color caused by the reaction between chlorine and iron, you can follow these steps:

1. Test the water: Start by testing the water to confirm the presence of iron. You can purchase a water testing kit or consult a professional to determine the exact iron content in your water.

2. Consider a pre-treatment: Based on the iron content, you might need a pre-treatment method. One common method is using a sediment filter or a water softener to remove iron particles before chlorination.

3. Reduce chlorine dosage: If you're using chlorine as a disinfectant, you can reduce the chlorine dosage to minimize the reaction with iron. However, keep in mind that reducing the chlorine level might impact the effectiveness of disinfection, so it is important to strike a balance.

4. Use a chelating agent: Another approach is to add a chelating agent to the water, which can bind with iron ions and prevent them from reacting with chlorine. Common chelating agents include polyphosphates, such as sodium hexametaphosphate.

5. Consider filtration: In severe cases, where iron levels are high, you might need to consider using an iron removal filter. Different types of filters, such as activated carbon filters, oxidation filters or greensand filters, can effectively remove iron and other impurities from water.

Remember, the most appropriate method to remedy the water depends on the iron content and other factors specific to your situation. It is always recommended to consult a water treatment expert to assess your water quality and provide suitable solutions.