3 Colours Your Pool Water Could Turn and What They Mean

In an ideal world, your pool water would stay blue and sparkling effortlessly. However, every pool requires routine maintenance to stay clear and swimmable, and many pools will still experience periodic issues characterised by abnormal water colouration.

While you will want to consult a pool maintenance professional on many of these problems, understanding the main causes of each type of discolouration can help you begin the diagnosis process. In this blog, we list three potential colours your pool could turn and explain why.

1. Black or Purple

A black or purple pool can look shocking, but these two types of discolouration typically come from one of two causes: excess manganese or a specific species of algae. In the case of manganese, the discolouration will primarily affect the general hue of the water, while algae will create spots on the sides of the pool.

Manganese reacts to chlorine, so you may actually notice this colour change immediately following a chlorine treatment. To get rid of purple water caused by manganese, hyperchrlorinate your pool. As the chlorine and manganese react, the metal will drop to the bottom where you can vacuum it up.

If your regional water contains manganese, you may need to add a stabilizer to your pool chemicals.

Unlike manganese, black algae usually requires professional removal, since this algae species has deep roots and rapid regenerative qualities. All types of algae, including black algae, thrive due to chemical imbalances in your pool water.

2. Brown or Red

Manganese is not the only metal that can come into your pool from your water source and change the water colour completely. Excess iron in your water source or iron contamination can leave your water any shade of brown, red or rust.

Consult with a pool professional to determine the best method for removing the iron from the water. Equipment for this task includes pool magnets that collect the foreign particles and shocking kits that cause the iron to float on top of the water for easy removal.

3. Green or Yellow

Green discolouration is the type most commonly found in any body of water, but this abnormal colouration also has the most potential causes. Your pool water could turn green due to:

  • Algae bloom due to inadequate chlorine, which may also make the water murky
  • Metal oxidation, such as copper particles that react with the pool chemicals
  • Pollen contamination from local plants

You should not swim in a green pool until you know the cause of the discolouration. While pollen is harmless, green algae and heavy metals can be hazardous to your health. Additionally, these pool issues can leave permanent stains and have other inconvenient side effects like green hair discolouration.

Have a professional conduct tests before you attempt to treat green pool water to ensure that you take the appropriate approach for the problem at hand.

Certain issues, like pollen contamination and certain algae species, can result in yellow pool water as well as green. Treat yellow pool water with the same caution you would use with green water.

Yellow pool water can also result from excess iron levels that aren't high enough to make the water rust coloured. In this case, as in any situation where the discolouration comes from the presence of metal contaminants, the yellowish colour is most likely to appear after a chlorine treatment because the chlorine causes a chemical reaction.

If you notice any discolouration in your pool, including those listed above, discuss your options with your pool maintenance expert. In many cases, misguided DIY efforts can turn a minor issue into a major or even permanent pool problem.

For reliable pool maintenance, trust the team at Shenton Pumps.