Uh-Oh, Tiny Black Bugs in the Pool After Rain? (How to Identify and Eliminate!)

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There’s little more in life that’s as refreshing as a dip in a crystal-clear pool on a hot summer day.  

But, as all pool owners know, the pool doesn’t stay clean on its own.  Whether it’s bugs, leaves, dirt, algae, rodents –all of these are things that most pool owners don’t want to see in the water.  

While many pool owners may feel they’ve seen it all, then along comes a new sight: tiny black bugs in the pool after rain.  The pool may have been sparkling clean before the rain, but now these small black insects are jeopardizing your next swim!

There are a few types of tiny black bugs that could be invading the pool after a rainfall.  Fortunately, while none of them are prone to causing much harm to people, they can definitely be irritating for multiple reasons.

Keep reading to know how to identify which type of tiny black bug has invaded your pool and how to get rid of them.

Types of Tiny Black Bugs in the Pool

If you’re trying to determine the type of bug in your pool, you’ll want to start by observing their behavior.  Are they jumping, swimming, floating, etc?  

It may also be useful to capture a few with the pool net or clear container to examine them more closely. Knowing what type of bug you’re dealing with can help you better understand how to control their population.

There are several types of bugs in the pool that could match the description of being tiny and black:  

  • Pool mites 
  • Springtails
  • Thrips

Fortunately, they can be distinguished from each other with relative ease.  

What are Pool Mites?

Pool mites, also known as water mites, may be found floating around your pool, especially after it rains.  Certain species may be black, brown or red.  

They are very small at only 2-3 mm in diameter, and may have the appearance of a tiny round spider.

Pool mites thrive in damp areas, and they live on wet soil, as well as on plants around your pool. Additionally, they consider algae and larvae floating around your pool a delicious meal.

Although they eat larvae and algae in your pool, they won’t feed on humans.

These mites can multiply very quickly, so it’s important to get rid of them as soon as possible.  As their numbers grow, they can attract predators such as the infamous backswimmers.

What are Springtails?

Springtails have been known to invade pools in high numbers.  Most species are often black, brown or gray. 

Springtails are often slender and very small at around 1/16 inch long –similar size to that of fleas.  They have antennae and a soft body.

Although small in size, they often come in large numbers which will easily attract the eye.  

While they cannot swim, they are great at floating on the surface of the pool.  Since they don’t have wings, they won’t be able to escape the pool.  

You can try to agitate the surface of the pool to force them to drown.  Otherwise, spraying dish soap around the perimeter is often enough to drown them as well.

What are Thrips?

Thrips are tiny, slender insects that are known to damage plants.  Thrips are usually small, measuring only 1 to 2 millimeters in length, and they can range in color from yellow to black.

They are capable of flying, which makes them highly mobile and able to move quickly. Thrips can be difficult to control, as they can reproduce quickly and hide in small crevices.

Thrips are one type of insect that you’ll want to keep away from the pool, as they are known to bite, especially in large numbers.  

Fortunately, thrips cannot swim and will drown fairly quickly.  They typically arrive near pools because they like nearby vegetation, or may be hiding from predators.  Once in the water, they often cannot escape due to the slick conditions.

What Happens After Rain?

So, you want to know why there may be an uptick of bugs in your pool after it rains?  There are a couple of reasons.

When conditions are moist around the pool after a rainfall, this can promote growth and reproduction of bugs.  The rain can also help some bugs travel farther, and potentially into your pool.

Vegetation near the pool may be also harboring those tiny black bugs.  When you combine rain with wind, it’s a favorable scenario that could blow them right into the pool.

Rainfall can also promote mosquito growth, which pool mites can latch to.  This means as mosquitoes get near your pool they could be carrying these mites with them.  

Additionally, when you receive heavy rain it will raise the pool’s water level.  If the level gets too high it can prevent the skimmer from functioning.  

Without the skimmer, the surface water stops circulating allowing leaves, bugs (such as those tiny black ones), and debris to accumulate throughout the pool.  

How To Get Rid of Pool Mites and Other Bugs?

Pool mites aren’t something that you have to just live with, as there are a few tips that can help you exterminate them.

Here’s how to get rid of pool mites and all other bugs, especially after it rains:

Tip #1: Get Rid of Algae

Many pool bugs rely on algae as their food source.  Getting rid of the algae is key to eliminating the bugs.

Scrub down all surfaces of the pool where algae may be hiding, and shock the pool.  

Periodic dosing with an algaecide will also help to keep the algae away for good.  

Tip #2: Skim Your Pool Daily

Skimming your pool on a regular basis using a pool net is essential to remove other organic meals that these bugs may feast on.

Pools with built-in skimmers will help keep the surface clean as long as the pump is running.  However, sometimes manual skimming is even more effective especially after a rainstorm has dirtied the pool.

Tip #3: Vacuum and Brush Your Pool Regularly

Vacuuming your pool is just as necessary as skimming it. That’s because it removes all the sunken debris and dead bugs. So, Use a pool vacuum to maintain the cleanness of your pool.

Additionally, don’t skip the brushing process because it loosens up any stuck contaminants and gets all tiny bugs inside hidden in small gaps.

Tip #4: Shock Your Pool

Shocking your pool using chlorine is a really effective way to kill all unwanted organic matter floating around the pool water.

The amount of chlorine required to chock your pool will depend on your stabilizer or cyanuric acid level.  Often raising the free chlorine level to 10+ ppm is enough to be an effective shock.  

Within 48 to 50 hours, the chlorine should go back to a safe level, which is often 1–3 ppm.

Tip #5: Adjust Landscaping

Bugs love to feast on plants, leaves, flowers and other vegetation.  While having nice plant life near the pool creates ambience, they could be the source of the tiny pests invading your pool.

Fortunately, there are certain plants that will repel pests, including lavender, catnip, rosemary, and sage.  

How To Keep Pool Mites Away?

As the saying goes “an ounce of prevention is worth a pound of cure,” it’s useful to know how to prevent those tiny creatures from getting into your pool and how to keep them away.

To do so, do the following:

  • Place all lighting fixtures as far from your pool as possible, because those bugs are mostly attracted to light.
  • Keep vegetation away from the pool because some of the water bugs feed on those plants. Or, choose pest repelling plants such as lavender, catnip, rosemary and sage.
  • Place the garbage cans away from the pool because they also house many bugs.
  • Remove any source of still water from your garden, like bird baths, outdoor water toys, or pet water dishes. Mosquitoes will breed in standing water, which can lead to more bugs around the pool.

Final Takeaway

Just like a pool turning green overnight, tiny black bugs in the pool after a rainstorm can be a frustrating problem for pool owners. However, by understanding the problem, taking preventative steps, and using effective elimination methods, you can keep your pool free of thrips and other pests. 

With a little effort, you can enjoy a clean and healthy pool for the entire swimming season.

Happy (Pest-Free) Swimming!

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