How to Get Rid of Mosquito Larvae in Your Pool

Many pool owners have a problem with mosquito larvae in the pool, and even the government recommends combating mosquitoes. But how do you remove the larvae from the pool water before they grow into bloodthirsty mosquitoes?

Mosquito larvae are best combated with long filter runtimes of 6 to 8 hours/day, a skimmer with a flap, a fine-meshed landing net, and proper water treatment using pool chemicals. In addition, mosquito larvae can be combated with a larvicide.

I show how to get rid of mosquito larvae in the pool water and effectively keep mosquitoes away from the property.

Why are mosquito larvae often in the pool?

Mosquitoes love water and therefore stay nearby. Especially standing water is an ideal breeding ground for mosquito larvae.

The pool, rain barrels, and puddles are such places, and as a result, many mosquitoes come to stay.

In addition, human blood is a food source for the two-winged parasite.

The mosquitoes don’t come from anywhere.

Especially if you are dealing with an unnaturally large number of mosquitoes in the pool, it can be assumed that the breeding site is nearby and, in the worst case, your own pool is used for this.

The mosquito eggs are difficult to spot. The problem can only be recognized as red worms in the pool later in the development stage.

But why – despite pool chemistry – are mosquito larvae in your pool?

This can be due to the following causes:

  • Too little disinfectant (chlorine, active oxygen, bromine, etc.) is used in the pool.
  • The filter run times in the pool are too short (less than 6 hours), and the food supply increases.
  • Standing water around the ridges is an ideal breeding ground for mosquitoes.
  • Open or leaky rain barrels in which the mosquitoes lay eggs.

Too little disinfectant in the pool water

Mosquito larvae may be present in the pool despite using pool chemicals – especially if you pour too little of the disinfectant into the pool.

The mosquito larvae feed on organic materials filtered out of the water. 

But, the larvae can only pupate and later hatch as a mosquito if there is enough food.

If you don’t use disinfectants in the pool water, there is a rich supply of organic substances in the pool that enable the larvae to develop from an egg to a full-grown mosquito.

Short filter run times

Short filter run times are a common reason why mosquitoes are present in the pool.

Many pool owners try to save electricity through short filter runtimes.

The problem is: If the filter runs for a short time, algae will multiply, and the pool water will turn green. Other organic substances are not filtered out, and an ideal food supply is created for the mosquito larvae.

Standing water is also ideal for mosquitoes to develop.

Standing water near the pool

Mosquitoes are not picky about their breeding sites, and the swimming pool is not always preferred.

Most of the time, the breeding grounds are near the garden.

In principle, a small puddle in the garden – through bumps, dead tree trunks, or manhole covers (street drains) near the garden – is fine for laying eggs.

Such breeding grounds can be destroyed with a larvicide – I will explain the use of a larvicide against mosquito larvae below.

Leaking rain barrels support mosquito larvae 

Rain barrels that do not have a cover are ideal breeding grounds for mosquitoes.

Even small leaks are enough for mosquitoes to lay eggs in the barrel.

So the pool doesn’t have to be the main source of mosquitos around the pool.

The problem can be solved quickly by covering the rain barrels with a lid or a mosquito net in the future.

Already contaminated water in the rain barrel must be treated to kill the larvae.

How to get rid of mosquito larvae in the pool

The mosquito larvae should not linger in the pool water and should be fought as quickly as possible.

The same applies to rain barrels and other breeding grounds outside the pool.

The worst thing you can do is pour some home remedy in the pool to kill the mosquito larvae.

During my research, I even came across the tip of pouring detergent or vitamin C into the pool water. Some pseudo-advisors recommend permanent shock chlorination against mosquito larvae.

These are tips that testify to the ignorance of pool maintenance and which it is best not to follow!

Any organic input into the pool leads to cloudiness and other problems such as foam in the pool water.

In the end, you didn’t achieve anything and only caused unnecessary pool maintenance costs.

But what can you do against mosquito larvae in the pool, and how are the larvae and pupae best removed from the pool water?

My tips are suitable for eliminating an existing problem with mosquito larvae and preventing them. Read more about this in the text.

1. Start water filtration against the mosquito larvae

My attitude towards pool maintenance is – as far as possible – to always avoid chemicals.

The pool chemistry pollutes the pool water above a certain limit, and in my experience, it is not always necessary.

In the case of a problem with mosquito larvae in the pool, I have already mentioned that the filter run times may be too short.

Running water prevents the mosquito eggs from developing into the larval stage, and in the best case, they are chased through the filter system.

Depending on the performance of the pool pump, the filter system should run between 6 and 8 hours a day. The water must run through the filter system at least once completely during this time.

Additional pool edge cleaning with a brush loosens breeding grounds and improves the cleaning effect against mosquito larvae.

In addition to filtration, I also recommend using a flocculant in the pool. The flocculant binds fine organic substances and enables better filtration.

No scientific study shows how well the flocculant works against mosquito larvae, but with regular use (every 14 days), the pool water remains clean.

In practice, using the flocculant does not lead to any problems with mosquitoes in the pool – you can find my helpful instructions on the flocculant via the link.

Tip: If the filter system is already running for more than 8 hours a day and you still find mosquito larvae in the pool, the pump is probably too weak.

In the blog, you will find instructions for calculating the necessary pump power for your pool.

2. Use a skimmer with a flap against mosquito larvae

The mosquito, the larvae, and the later pupa stay on the water’s surface to breathe air.

As a result, permanent cleaning of the water surface to get rid of the mosquito larvae in the pool is of great importance. Either a skimmer or an overflow channel is used for this.

Insects are best removed from pool water with a skimmer.

It is important with the skimmer that there is a flap. The flap increases the suction on the water surface and increases the effectiveness against water bugs in the pool.

Don’t buy a skimmer without a flap!

The mosquito larvae and other insects swim out of the skimmer without a flap as soon as the pool pump is switched off.

Tip: Skimming is made easier if the floor drain – if available – is partially closed beforehand.

3. Use a pool net against mosquito larvae

In addition to water circulation and the use of a surface skimmer, a landing net is an effective tool for removing insects from the pool or whirlpool.

But you can only do that with a particularly fine-meshed surface landing net.

The net mesh must be fine enough to fish the tiny red worms out of the water. Otherwise, they will end up in the pool again.

Unfortunately, most nets are made of pure plastic and tend to break – take care when handling them.

A net costs a few dollars, and I advise trying out several models until you find the right one – experience has shown that high-quality pool nets cost a little more.

4. Application of pool chemistry to kill mosquito larvae

The mosquito’s eggs are laid on the water’s surface in the pool. These are quite resistant and, depending on the species, can even survive in dry places.

It is believed that chlorine and other disinfectants inhibit the development of the eggs – unfortunately, I have not found any scientific research to prove this.

However, some pool owners report successes using a pool shock or bleach.

Excessive use of chlorine is no guarantee to kill the eggs and mosquito larvae. If misused, there is a problem of over-chlorination of the pool water.

What I do know, however, is that mosquito larvae need organic food to develop.

With the proper use of pool chemistry and sufficient filter run times, the nutritional basis is withdrawn, and there is a high chance that many mosquito larvae will die.

5. Use larvicides against mosquito larvae

The larvicide is an insecticide (product type 18 of the Biocide Ordinance) and one of the most effective means of combating mosquito larvae in the pool.

These form a monomolecular surface layer that acts as a physical barrier and prevents the larvae from breathing on the surface and thus being killed.

But be careful: Not every product is suitable for the swimming pool.

I recommend larvicides that are used as a registered biocide for mosquito control.

Larvicides are used in all hatcheries that cannot be removed, such as rain catch basins or gorges.

These products are available as tablets, liquids, or granules.

According to the instructions for use, proper use of the larvicide is important for effectiveness.

The use of larvicides has been classified as safe for humans, but as with all chemical agents, allergic reactions occur in rare cases.

Overdosing may cause skin damage.

Tip: Estimates of the duration of the effectiveness of the larvicide, which is stated on the product label, differ in practice.

Are mosquito larvae dangerous to humans in the pool?

The mosquito bite is uncomfortable and causes itching.

Much worse, however, is the risk of disease transmission through invasive mosquitoes – this is understood to be the mosquito species introduced into Europe that cause economic and health damage.

There are now 1306 non-native insects in the US that have established themselves, including many invasive mosquito species.

The favorable environmental and climatic conditions improve the population, and the risk of transmission of chikungunya, yellow, dengue, and zika viruses increases due to the mosquito bite. Source.

But are the mosquito larvae in the pool dangerous for people?

An open pool attracts mosquitoes and serves as an ideal place to lay eggs. Mosquito larvae develop from the eggs and can also be recognized as red worms in the pool water.

The mosquito larvae filter organic nutrients and do not yet feed on blood. In addition, the larvae breathe air and therefore prefer to stay on the surface of the water.

Red mosquito larvae are harmless to most people, but some experience allergic reactions swimming in the pool.

The allergy to mosquito larvae takes the form of itching – similar to a bite – and reddening of the skin.

The risk of disease transmission through adult mosquitoes and the allergic reactions to red mosquito larvae in the pool are reasons enough to fight the larvae.

Do you have any further questions how to get rid of mosquito larvae?

Contact me at @contactswimfool on Twitter, Facebook, YouTube, or Pinterest – I’ll be happy to help you personally.

Good luck in the fight against mosquitoes in your pool!

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Hi. I'm Max Berg. I've been in the pool industry since 2015 and have always felt drawn to water. I'm the author behind swimfool.com, where I share my years of experience in pool maintenance and give helpful tips on keeping a swimming pool or hot tub clean. My tips reduce the costs of water treatment and protect the environment.

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