Were you planning a pool party with friends this summer, only to cancel it last minute because you couldn’t get rid of the hideous green water?

Well...sorry about that! We understand nothing disappoints a pool owner more than a green pool and a cancelled party. But what’s the fun of swimming in water that looks like it hasn’t been cleaned in ages?

So the question arises, what causes perfectly blue water to go green? In this guide, we've got the answers to all your questions. To help you even further, we've added some quick tips on regular pool maintenance.

Green Pool Photo

What Makes Pool Water Turn Green?

There are several reasons why the pool turns green. While algae formation is the most obvious answer, there are certain other elements that can alter the colour.

1. Rain

Rain disrupts the chemistry of the swimming pool, which is otherwise carefully balanced. As a result, the pH levels are altered and the chlorine and mineral content in the pool is diluted.

A rainstorm brings debris, leaves and dirt with it, all of which gets deposited in the pool. This decomposes, leading to the formation of phosphates in the water.

In addition to this, thunderstorms and lightning flashes contain nitrogen that is washed into the pool by rain. This nitrogen provides excellent fodder to the algae and sustains its growth.

Once algae spores find a foothold and the perfect climate to grow, they start multiplying quickly and your pool can turn green overnight. Not only is algae growth awful-looking, but it also irritates your skin and causes numerous problems such as eye and ear infections, among others.

Keeping the pool covered during rain or thunderstorms is recommended to prevent water and other debris from coming into the pool and disrupting its chemical balance.

2. Wrong Amount Of Chlorine

The most common reason for the pool turning green is a disrupted balance of chlorine. Adding Chlorine to your pool keeps the growth of algae at bay, making the water safe and clean for swimming. It acts as a disinfectant and also eliminates materials such as chloramines. Thus, an imbalance of the chlorine level in the water leads to a spurt in algae growth.

An excessive amount of chlorine can also lead to discolouration of the pool. Often, people make the mistake of resorting to over-chlorination or a chemical shock to restore the chlorine balance. However, if not done right, this can oxidize the metal in your pool causing the water to turn luminescent green.

3. Pollen Buildup

Another reason why your pool water might go green is the presence of pollen in it. The wind carries pollen from nearby trees and flower pots to the pool. The filter of the pool is unable to get rid of this pollen and its accumulation over time leads to the pool turning green.

Even though it might give your pool a murky, green look and is often mistaken for algae, pollen has no harmful effects on the body. That said, it can clog the filter. Besides, pollen blooms get worse during the spring season, and it is especially at this time that you should take good care of the pool to avoid pollen buildup.

Before you do that, remember to differentiate between algae and pollen, and then treat it accordingly. Algae is slimy and sticks to the walls of the pool, whereas pollen floats on the surface.

4. Metals

Heavy metal presence in the water can lead to staining. For example, copper is the most common metal found in water and is also present in the algaecides you use for pool cleaning. Thus, copper oxidizes in water because of the presence of chlorine and acquires a light green hue.

Besides copper, several other metals like silver, iron and manganese. are present in the pool water. They are usually involved in the production of pipes and pool parts. However, not all of them turn green when oxidized.

It becomes challenging to differentiate between an algae invasion and the oxidation of copper in the water. We recommend determining the level of chemicals in the pool by using metal test strips.

5. Malfunctioning Filter

A filter system that is not well-maintained can fail to collect debris or prevent algae buildup.

An ineffective filter will let the pool water stagnate, leading to it turning green. It is important to remember that the filter system does most of the pool cleaning and without it, your water will be the hub of algae growth, mould, dirt and bacteria.

If you notice an excessive accumulation of dust particles or algae formation in the pool, try cleaning the filters and replacing them if needed.

6. Weather Conditions

Algae seek warm, humid temperatures for growth. As a result, summer and monsoon months are a time for them to thrive. It is essential to use more potent chemicals like algaecides to eliminate the increase in algae buildup.

Besides, clean the filters often during summers for efficient removal of algae and bacteria.

How To Fix The Green Pool Water?

Getting rid of a murky, green pool is not as difficult as it seems. All you have to do is follow a few essential steps and you'll have thriving and sightly blue water back in no time.

You don’t want to have the hassle of cleaning a green pool regularly. Routine maintenance does not allow algae or bacteria to multiply and the pool is ready with clear blue water whenever you want to swim.

Step 1: Test The Pool Water

A chemical kit can test the pH and chlorine levels in the pool. This helps determine the extent to which the water needs to be treated. If chlorine levels are acutely low, you'll have to 'shock' the pool. The ideal pH level is 7.4.

If the pool turns green as a result of the oxidation of copper in the water, then a test kit can detect that.

Step 2: Clean The Filter

Before carrying out any treatment, make sure to clean the filter and get rid of debris, leaves, sticks or any other material that might be blocking it. If your filter is blocked, its efficiency is reduced, and in that case, even a chemical treatment cannot combat algae growth. Your filter should be unclogged and functional.

Step 3: Brush The Pool Sides

Use either an algae or a regular pool brush to clean the edges of the pool. Algae cling to the walls and sides of the pool and need to be meticulously removed. Scrub the sides, the floor and the walls. After this step, your pool will be ready for chlorine infiltration.

Step 4: Shock The Pool

The fourth and most crucial step in cleaning a pool is treating it with chlorine. In the process of “pool shock,” a high level of chlorine, which is tough enough to kill algae and bacteria, is introduced into the water. Algaecide is also used in the treatment of pool water.

You can shock the pool more than once, depending on the algae buildup. Once that is done, let the water rest for a day and then run the filter till it becomes crystal clear.

Step 5: Re-test The Chemical Levels

Use a swimming pool kit once again to test the water for chlorine levels, pH levels and alkalinity. If everything is well balanced, the pool is ready for use.

How To Maintain The Pool?

Pool Maintain Photo

The best way to avoid green pools is regular maintenance, which is not much of a hassle. Just keep a few crucial points in mind and you'll be good to go.

Tip 1: Wipe and Scrub The Pool Regularly

Wipe the tiles of the pool weekly, and scrub the sides to prevent the buildup of algae. There are skimmer baskets located on the sides that absorb dirt and debris and require routine emptying.

Tip 2: Clean The Pool Filters

Sand filters need cleaning fortnightly, whereas cartridge filters are cleaned every month and DE filters need cleaning every five weeks. Regular maintenance of the filters will enhance their longevity and save you from expensive filter replacements.

Tip 3: Test The Pool's Balance

You should check the pool's chemical balance, the chlorine concentration and the pH level at least once a week.

Final Thoughts on cleaning a green pool

With that, we come to the end of our guide. We hope getting clear blue water for your swimming pool will now be an easy task.

Neglecting pool maintenance is one of the most common mistakes owners make. Long story short, it is essential to eliminate algae buildup, prevent oxidation of chemicals and remove all grime and dust from time to time. After all, why should murky green water hinder your summer escapades?

Do let us know if you have any queries in the comments below.

Till next time, enjoy the pool party!

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