How To Remove Yellow Stains From A Pool Liner – Complete Guide

Have you noticed yellow stains on your liner, and more exactly a yellow coloration of your water line? How to avoid these spots? How to get rid of it?

The water line of a swimming pool is a very sensitive area (especially when it is equipped with a liner). This is where most of the pollution is concentrated, resulting in a brown or yellow coloration of the water line.

The fouling of the water line of the swimming pool is slow and regular. It is caused by fatty substances floating on the surface of the swimming pool, including, in particular: the fallout from the combustion of hydrocarbons (chimneys, proximity to a road or an airport, etc.), body oils and pollution linked to the plant environment.

It is frequently observed that the water line is more easily marked on the sides of the swimming pool, exposed to the sun . In fact, the pollution of the membrane is activated or aggravated by solar radiation.

A yellowish coloration on the water line of your swimming pool may appear.

This coloring results from an undesirable chemical reaction between certain anti-UV agents incorporated in sun products (such as Benzotriazine and Benzotriazole) and the presence of copper in the swimming pool water.

This coloring is limited to the water line (emerged part of the liner) because it is on the surface of the pool that the sun creams and oils, which are insoluble in water, float.

Products That Will Clean The Yellow Stains

  • Regular maintenance of the liner water line

The coloring of the water line is easily removed by a weekly maintenance , using a liquid, non-abrasive cleaning product (varnished membranes), provided for this purpose.

You can also use a magic eraser to scrub your water line.

  • Beware of limestone on the walls of your pool

The lime deposits on the water line of your swimming pool facilitate the adhesion of fatty substances and complicates its cleaning.

Lime is easily removed by using a suitable acidic cleaning product 

It is also possible to use a mixture of isopropyl alcohol and water (1/1). Very stubborn pollution is generally removed with ethyl acetate or THF, but these modify the appearance of the surface (shine) and also remove the varnish and the pattern, in the case of a coating printed or varnished. The use of ethyl acetate, THF or, more generally, PVC solvent, is therefore strictly prohibited with varnished and / or printed membranes.

  • Watch out for copper and sunscreen in your pool

Avoid an excess of sunscreen and especially sun oil (the worst!) And take a shower before swimming.

Avoid adding copper to your pool (copper sulfate).

How To Eliminate The Yellow Stained Water Line For Good

In order to remove the yellow stains on the liner or the PVC membrane, the following curative treatment must be carried out:

1st week:

1- Increase the water level of the pool to cover the stained area

Day 1 :

2- Perform shock chlorination at 10 ppm of free chlorine

3- Adjust the pH of your water to 7

4- Pour into a skimmer 1 cap (40 ml) of metal inhibitor (FERAFLOC) for every 50 m³ of water

Day 4:

5- Pour a new dose of 40 ml of FERAFLOC for every 50 m³ of water

Day 7:

6- Backwash the filter

NB : Let the filtration run continuously, throughout the treatment and repeat the above operations for 5 weeks.

How To Remove Stains From a Pool

It is the dread of any pool owner: seeing spots appear on the coating of a pool. Often difficult to remove they quickly become a nightmare. All stains are not cleaned in the same way, for the simple reason that they do not all have the same origin. The treatment will also depend on the coating of your pool: liner, coating, or fiberglass. Here is our guide for how to remove stains from a pool.

How To Remove Stains From a Pool Liner

Brown spots. Removing brown spots on the liner of your pool can be a relatively easy operation if they result from the presence of organic waste or are a sign of deposits of dead algae. On the other hand, it promises to be more delicate if it is a question of micro-mushrooms which, in reality, have developed behind the liner, on the concrete part of your swimming pool, and appeared by the effect of porosity. It is generally the consequence of humidity that settled between the coating and the concrete.

How do you know if it’s algae or fungi?

If the spots reappear quickly after rubbing them, it is fungi. In this case, do the following:
Lower the pH to 6.8 and stop the filtration. Thus, the pores of the liner will dilate and the treatment will be more effective. Then, if you have only a few isolated sections, bring gloves, a chlorine tablet, and diving goggles and then rub in small circular movements, without pressing too hard, on the stain.

On the other hand, if the spots are almost everywhere in the pool, pour with a watering can sodium hypochlorite or, failing this, bleach as close as possible to the spots.
Finally, raise the pH to 7 or 7.2 and then filter the pool water continuously for 72 h before washing the filter.

If the waterline has turned yellow. This is due to the presence of floating fatty substances on the surface of the water. Even with regular maintenance of your pool, sunscreens, are formidable. To prevent the appearance of this famous yellow line, think of rubbing the edge with a suitable product, once a week.

To prevent the appearance of limescale, which promotes the adhesion of fatty substances, by also using an acid cleaning product. If, on the other hand, the water line is crusted, do as follows:
Fill the pool so that the water largely covers the yellow line.

Do shock chlorination. Set the pH to 7. Pour a metal inhibitor into the skimmer at the doses indicated (generally 40 ml for 50 m3 of water). On the 4th day, pour a new dose of product. On the 7th day, backwash the filter. Leave the filtration continuously on for the duration of the treatment.

Rust stains. They reflect the presence of metals in water (iron, copper, manganese). To remedy this, apply the specific products using a sponge after putting on gloves. You can also try white vinegar. To do this, attach a sponge to the end of a hollow tube and pour the liquid into it. Then rub on the stains.

Pink or Red spots. Viscous in appearance, they first appear on plastic surfaces (water toys, ladders, etc.). To make them disappear, lower the pH to 7 and scrub the stains with a sponge. Then do a shock treatment or use an algaecide.

For optimal efficiency, also leave contaminated objects in the water during the operation. The filtration system must also work continuously. Then 24 hours later, raise the pH to 7.2 and 7.6 and leave the filtration system on for another 72 hours. Wash the filter every day before the treatment. You can remove stains on a liner by using a specific cleaner sold in specialized stores.

You will apply it using a sponge or a glove, and scrub in circular movements. You can also use silver stone, which is a natural clay-based solution, or white vinegar.

How To Remove Stains From A Fiberglass Pool

Red, Black, Brown, Blue/Green spots. This may be due to the decomposition of organic matter (leaves, insects, etc.) or an excessive supply of metal ions.

What to do? The treatment of these stains on your fiberglass pool will take place over a week. On the first day, Acidify the pool by reducing the pH to 6, then carry out shock chlorination. Then add a ferrous ion product using the correct dosage. On the 4th day, add another dose of the same product. On the 7th day, backwash the filter. In the end, check that the pH has risen between 7.2 and 7.6 and then stabilize it. For prevention, be sure to keep the pH between 7.2 and 7.6.

Brown or Green spots. Have algae formed on the bottom and walls of your pool? To be sure, just see if they disappear on contact with a chlorine tablet. If this is the case, treatment is necessary. Practice shock chlorination then adjust the pH of the water to between 7.2 and 7.6 as well as the hardness. Run the filtration system all the time.

Then, do a flocculation treatment to increase the fineness of filtration and eliminate the algae in suspension. Allow a day to pass then brush the walls, wait for the residue to form at the bottom of the pool, and vacuum them directly to waste. Return the filtration system to normal operation.
To prevent algae from returning, it is advisable to use a pool cover which will thus block the photosynthesis process.

Brown or Black spots. They are undoubtedly fungi, which have formed due to insufficient filtration, or random cleaning of the pool. To remedy this, you will need to lower the pH to 6 in order to acidify the water, before initiating shock chlorination.
Note that to avoid the appearance of fungi, the pH should be kept around 6.8 and the chlorine level should be at least 1.5 mg / l.

White or Grayish spots. If they are rougher to the touch, it is tartar. Here is the solution. Acidify the pool water by reducing the pH to 6 and then, allow the pH to rise alone between 7.2 and 7.6. If it has not gone back far enough beyond the 7th day, use a product. If this was not enough to remove the stains, you will have no choice but to empty the pool to descale it.

Warning! Before emptying the pool, it is imperative to check that there is no water under the bottom, otherwise, it could rise and irreversibly damage your installation.

If you do not want limestone to return to the walls and bottom of your pool, you must regularly analyze the pH of the water and adjust it if necessary, between 7.2 and 7.6. In addition, it is essential to treat the water regularly (at least 3 times a year) with a suitable anti-lime.

Discoloration spots. This is no doubt due to repetitive shock treatment. The chlorine damages the Gelcoat coating of your fiberglass pool. Unfortunately there is nothing to do, except to empty the pool and redo the coating.

The water line turns fluorescent yellow. It is the sign of the presence of benzotriazoles or debenzotriazines present in sunscreens. Here are the steps to follow. Raise the water level to above the yellow line then adjust the pH between 7.2 and 7.6. Once it is done, carry out shock chlorination and add a metal-capturing product in the correct dosage.

In addition, if you do not clean the water line quickly after the first signs appear, then the coloring could become permanent.

Brown marks at the waterline. Fats, in addition to remaining on the surface, trap dirt. To overcome it, the water line must be cleaned regularly with a suitable product whose role is to prevent stains from becoming permanent. If the waterline resists this cleaning, lower the water level below the coloring and clean with a descaler.

How To Remove Stains From A Concrete Or Plaster Pool

Heavy metal is a pool’s enemy. I’m talking about the invisible metals dissolved in your pool water from sources like rain run-off, pool equipment, saltwater pool systems, or even your concrete pool deck surface. Bits of metal like screws or hairpins can make a nasty rust stain.

It’s important to know what kinds of metals are creating the stains in your pool. Here’s a pool stain chart as a guide for metal stain identification in pools.

Metals are certainly not the only cause of stains in a plaster-surfaced swimming pool. Leaves, berries, bugs, suntan oil, or even your water-loving dog can all contribute to staining. For plaster pool stains is to always start with the brushing and shock before going in with a bunch of trial and error stain removers.

These types of stains can be cleaned with good old fashion elbow grease using a combination of a PoolStone and pool shock. Pouring a bit of pool shock directly onto a stain works similar to bleach and is ideal for plaster surfaces.

Sequestering agents, commonly called Stain & Scale chemicals, can help keep minerals and metals in solution, locked up tightly at the molecular level, so they won’t precipitate, mix with other particles, and then attach to your pool surfaces.

Other Types Of Stains: These can include pool stains from mineral scale-like calcium and metals like copper, iron, or manganese. Minerals can come out of solution in hard water, and metals can enter from fill water that is high in metals, or from copper pipes or a pool heater exchanger – when water balance is not correct.

Removing Stains from a Plaster Pool

Granular pool shock or EZ Stain Remover for organic stains
Sequestering agents or A+ Stain Remover for metal stains
Stain Eraser or PoolStone for mineral stains
Enzymes for oily, dirty stains
Acid Washing for all plaster, tile and coping stains
Keep pool water balanced and brush often

Once again, having the correct water balance is important. Poor water balance can become corrosive or scaling, and both conditions can cause plaster pool stains by making it easy for minerals and metals to come out of solution.

Can You Swim In A Green Pool?

The question you are asking your self is can I swim in a green pool? The answer is NO. In this article, I will explain why pool water turns green and what that water can do to you if you swim in it.

Why Does Pool Water Turn Green?

1 There is an imbalance in the PH levels of the pool water.
2 The Chlorine levels are too low.
3 The alkalinity levels are too low.
4 The Oxidized Metal quantities example copper is too high. (High acid levels, Metal Components in pool equipment, Copper heater elements)
5 Excessive quantities of Pollen are in the water.

Here’s Why You Should Not Swim In A Green Pool

When your pool is green that means there is an imbalance in the PH levels of the pool. If the PH levels are out this means that the pool water is not sterilized.

When the pool water is not sterilized there is an opportunity for algae, bacteria, and pathogens (microorganisms that can cause disease) to be present and grow.

If this is the case, then if a swimmer has an abrasion on their skin, there is a potential for infection and a possibility of incurring a rash or folliculitis (inflammation of hair follicles).

If the pool water has any form of algae and bacteria in it, it will be the ideal breeding ground for mosquitoes and other insects that thrive in these conditions.

Excessive amounts of oxidized metals can turn a swimmers’ hair green and there is a good possibility that your pool walls will be stained.

High levels of the copper content in the pool water can irritate your mouth, eyes, and nose, cause headaches, nausea, vomiting, stomach cramps, dizziness, and diarrhea.


It is not advisable to swim in a pool with water that is any color than clear blue. There are too many health problems that a person can incur from swimming in a green pool.

Rather sort out the PH levels first. Get the pool water crystal clear so that you and your family can enjoy the pool with no issues.

What Is A Pool Skimmer? How does A Pool Skimmer Work?

There are essentially two types of pool skimmers. One type has a net attached with a long pole which is used to manually remove leaves and debris out of a pool. The other type is built-in as part of the pool filtering system to remove debris and leaves.

They are both important and have similar functions for keeping a swimming pool clean. I will be explaining how they work, how to use them and how to care for them.

What Is A Pool Skimmer?

Pool skimmers are rectangular plastic inserts, that fit into the upper side of a pool wall. They contain a weir and a basket which has lots of small holes in it. A pool skimmer stops and traps large leaves and debris from reaching the pool pump and filter. This is the first stage of filtering in a swimming pool filtering system.

Pool Skimmer

On top of the skimmer, there is a hatch or lid where you can gain access to the basket. Within the skimmer on top of the basket, there is a detachable lid with a hole in the middle that allows you to connect a hose for manual and automatic vacuuming.

The other type of pool skimmer is the one that floats and moves around on top of the water and has the same function as the built-in pool skimmer.

How Does A Pool Skimmer Work?

A Pool Skimmer is the starting point of a swimming pool filtration and circulation system. There is a suction pipe located at the bottom of the skimmer underneath the basket. When the pool pump is on the pool water is drawn through the skimmer towards the pool pump causing a suction.

The skimmer uses a mechanical skimming action that works with the pool water level and the flow of water over the weir. Water is drawn into the skimmer which moves over the skimmer flap (weir). The skimmer flap (weir) adjusts its self automatically according to the pool water level and suction of the water. As the water moves over the weir the speed of the water increases causing a skimming action, thus pulling any debris and leaves with it.

Diagram Of How A Pool Skimmer Works

From there the water passes through the basket on its way to the pump and filter. The basket has holes in it which trap leaves and debris that are bigger than the holes of the basket.

This is the pool filtering system’s first line of defense to trap bigger debris before it enters the pump and main filter. Therefore allowing the main filter to filter only the smaller contaminants from the water. Without a pool skimmer, the main filter will get blocked very quickly.

When the pool pump is off, the skimmer flap (weir) moves vertically and closes off the skimmer inlet hole thus preventing any debris and leaves from reentering the pool.

Another helpful addition to the skimmer basket is a pool skimmer sock.

Pool Skimmer Sock

A Pool Skimmer Sock allows the skimmer basket to trap even finer debris. A pool skimmer sock comes in handy when you have a green pool full of algae. The sock traps the algae before it blocks the main filter.

When you are filtering a green algae pool, you will need to replace the skimmer sock a couple of times depending on the severity of the algae bloom.

What happens is that the skimmer filter sock has small holes and will get clogged very quickly. Therefore causing a restriction on pool pump flow which creates air in the system. There will be no movement of water, therefore, no filtration and pump damage can occur. Be present when using skimmer filter socks with a green, yellow or black algae pool. If your pool has a skimmer equalizer line built-in then you won’t have this problem

These filter socks stretch over the top of the skimmer basket. They are made from a strong flexible ultra-fine mesh material.
The filter socks are designed to trap small debris like hair, pollen, algae, oil, grass, bugs and any other debris before it reaches the pump and filter.

Giving longer service life to the pump and filter. When the socks become blocked they are designed to be washed out and reused many times over.

Do not dissolve chlorine tablets in the skimmer basket when the sock is on as they erode the sock.

Types Of Pool Skimmers

In-Ground Pool Skimmer

In-ground pool, skimmers are surface skimmers made from durable plastic (or PVC) or precast concrete. The skimmer is built with a tank and an opening on the upper side. They are placed on the upper part of the pool wall. The swimming pool water level usually fluctuates between half and the bottom of the skimmer opening. More than one skimmer can be added to a pool depending on its water capacity.

The positioning of in-ground pool skimmers in relation to the return jets is critical for pool circulation.
In-ground pool skimmers have a movable flap called a weir. The weir opens or closes according to the pool’s water level and flow of water. The weir will open when the pool pump is on.

In-Ground Pool Skimmer

The weir creates a skimming action ( increase in water speed) as a thin layer of water flows over it, pulling floating leaves and debris into the skimmer basket.

When the pool pump is off the weir closes and traps the debris in the skimmer. Debris cannot flow back into the pool.

It is good practice to remove and clean the skimmer basket of debris at least once a day. Being blocked it can put an unnecessary strain on the pool pump.

An in-ground skimmer should have an equalizer line installed. This helps to prevent air from entering the system if the water level drops too low or the skimmer basket gets blocked.

Above Ground Pool Skimmer

Above-ground pool skimmers either hang off the side of the pool frame with a bracket or they are free to float on top of the water.

Above Ground Pool Skimmer

Depending on the above ground pool brand, there might be a precut opening in the pool liner for an integrated pool skimmer to be fitted. It is now becoming popular to fit these integrated skimmers to above ground pools.

The only thing here is you would need to cut the hole in the liner correctly otherwise the whole pool liner will have to be replaced. This is either a DIY job or if you are not confident have a pool specialist to install the skimmer for you.

Automatic And Solar-Powered Pool Cleaners

The automatic and solar-powered pool cleaners are becoming increasingly popular with pool owners.
The automatic cleaner works with the return jets of the pool.

An automatic cleaner is connected with a pipe to the return jets and how it works is that as the water gets returned from the pump back to the pool it first enters into the automatic cleaner basket where the water is forced to rotate like a whirlpool. Then sucks the surrounding water and debris into the top and down into the filter bag. The debris gets trapped in the filter bag and the water returns back into the pool.

Automatic Pool Skimmer

This helps to reduce the load on the suction skimmer and weir, which in turn cuts down on the load of the main filter. Unfortunately, it only works when your pool pump is switched on.

A solar-powered pool cleaner works on solar power and internal rechargeable batteries. The batteries are charged by the sun’s energy during the day which powers the cleaner. The solar-powered cleaner can be used for in-ground and above ground swimming pools.

Solar Powered Pool Skimmer

A small electric motor drives a rear paddlewheel to move the cleaner through the water, while a front paddlewheel scoops the surface debris into a collection tray. The rechargeable batteries allow the solar-powered pool cleaner to work in overcast weather conditions, in the shade and even after sundown. The cleaner shuts down automatically when its charge reaches a certain level. The cleaner stays like this until it gets enough sunlight to power up again.

Certain solar pool cleaners have a chemical dispenser built-in to take pool chemical tablets. This disperses the chlorine or clarifier chemicals more evenly in the pool. Thus being more effective.

When To Clean A Pool Skimmer Basket

Your pool skimmer is the first line of defense within the pool filtration system. You don’t want the skimmer basket to get to full and then not cope with the debris it has inside it. Eventually, that debris will get soft and broken up into smaller pieces and sucked into the main filter.

How often you need to clean out the skimmer basket also depends on weather conditions and what type of plants and trees you have close to the pool. Neglecting skimmer basket cleaning will give you more work in the long run.

The big question is how often should you clean out the skimmer basket. My answer is once a day. If you have two skimmers clean both out daily. When you clean the basket out you will be able to keep track of what debris is in your pool.

When the skimmer basket gets cleaned daily there is less chance of debris getting to the pump and main filter as well as extending the life of the pool pump as it won’t have to work so hard when the skimmer basket is full and restricting pump flow.

How To Clean A Pool Skimmer

  1. Firstly turn the pool pump off.
  2. Then remove the cover of the skimmer to gain access to the skimmer basket.
  3. Either your skimmer will have a turn-lock so remember to turn the basket counter-clockwise before removing. Or the basket just pulls straight up.
  4. Empty the skimmer basket and it is advisable to spray all the small debris that sticks in the holes out with a garden hose.
  5. Replace the basket back into the skimmer and turn the basket clockwise if you have the turn-lock type.
  6. Replace the skimmer lid and turn the pool pump on.

How To Clean A Pool Pump Basket

Firstly turn off the pool pump.

  1. If your pool pump is below the pool water level. Turn the multivalve position to CLOSED.
  2. Block the return jets with a plug.
  3. Remove the skimmer basket and block the hole with a plug.
  4. Now no water can gravity feed from the pool to the pump.
  5. If your pool pump is above the water level then skip step 2.
  6. Remove the pool pump lid turning it counter-clockwise.
  7. Take out the basket and clean it thoroughly with a garden hose.
  8. Inspect the basket for cracks and holes as they are plastic and become brittle over time. (Replace Basket If Necessary.)
  9. Inspect the pump lid o-ring for cracks or tears. (Replace If Necessary)
  10. Replace the basket into the pump. You may add petroleum jelly to the o-ring to ensure a good seal.
  11. Refit the pump lid turning it clockwise. Do not overtighten. Only hand tight.
  12. Remove the skimmer basket plug and replace the skimmer basket.
  13. Remove the return jet plugs.
  14. Turn the multivalve position back to FILTER.
  15. Open the AIR RELIEF valve on the main filter if you have on.
  16. Turn the pool pump back on.
  17. When only water is coming out of the air relief valve, then close it.
  18. The pool pump should now be primed and circulating the water throughout the system with now air.

Why Should You Keep Your Pool Skimmers Clean?

A pool skimmer is extremely important for the filtration of any swimming pool. It is the first stage of the filtration process in the pool system. Keeping your skimmers clean is half the battle won when you want a sparkling pool.

Remember cleaning out the skimmer baskets daily will keep them free of excess debris and the pool pump will be able to circulate the correct amount of water all the time resulting in a cleaner healthier pool.

There will be less strain on the pool pump, less debris moving through the main filter and less time will be spent adding unnecessary chemicals to your pool. Resulting in a cleaner pool.