20 Common Pool Maintenance Mistakes

Written by Michael Dean
April 3, 2024

maintaining a swimming pool with a hazard sign next to them

As a proud swimming pool owner, you probably never miss your regular cleaning and testing routine, right?

Sure, you’ll say. Nobody has to know that you haven’t emptied the filter in three weeks or that there was a dead mouse floating in the deep end last night because you forgot to use the pool cover. We’re all human. We make mistakes.

Let’s help you avoid some pool maintenance mistakes that everyone occasionally makes.

Main Takeaways

  • Some common mistakes when cleaning include: backwashing too frequently, not brushing the pool, and removing algae with an automatic cleaner.
  • Common mistakes with chemistry and testing include: not maintaining proper chemistry levels, not testing the water weekly, and not adding winterizing chemicals when closing the pool for the season.
  • Some common mistakes with the pool filter are: running it for less than 8 hours a day and not cleaning the filter often enough.
  • When shocking the pool, ensure you shock after dark and do not add the shock directly into the skimmer or directly into the water.

Common Mistakes When Cleaning

Here are some common mistakes you can make when cleaning your pool.

Mistake #1: Backwashing Your Pool Filter Too Frequently

We’re not talking about that gross act of spitting half your drink back into a cup and handing it off to your friend. Backwashing, in this context, is essential for your pool’s integrity.

Over time, debris builds up inside your pool’s filter media. It cleans the dirt ingrained on the surface by pushing pool water through the media (typically diatomaceous earth or sand) and exiting through the drain port of your filter’s backwash valve.

Backwashing is fundamental to pool maintenance, but you don’t want to overdo it.


Watch your filter tank’s pressure gauge. After proper backwashing, the pressure gauge should read between 10 to 15 PSI (Pounds per Square Inch). If the gauge is flirting with 20 psi and higher, you may have a little problem.

It may surprise you, but the filter will actually function better with a bit of gunk, but only up to a level. More junk in the filter helps capture smaller particles. Still, you lose that advantage once the gunk raises the pressure reading to about 10 psi over baseline.

Once the filter’s pressure tops 10 psi over the recommended range, it’s probably time to empty it of debris. Clear the excess goop, give it another backwash, and watch the pressure return to optimal levels. For more, read my complete guide on solving high pool pressure.

Mistake #2: Failing to Brush Your Pool

All pool owners know it’s crucial to vacuum the pool. Vacuuming the pool has become a zen-like pastime, like mowing the lawn. It’s important to vacuum often to keep grime and algae from accumulating in the pool water.

However, just as you need to brush and floss your teeth, your pool needs regular brushing to stay in top condition. Always brush your pool before vacuuming for the best results.


Use an extra-wide, heavy-duty aluminum pool brush with curved edges for quick and deep cleaning. Be sure to cover the difficult-to-reach spots. Problem areas include crevices and corners, stairs and steps, behind ladders, and the waterline. Brush at least once per week or multiple times if the pool is heavily used or quickly develops grime.

Mistake #3: Removing Algae With an Automatic Pool Cleaner

When algae builds up, pool ownership can sometimes feel like a drag. Many people try to snatch back their precious time by firing up an automatic pool cleaner. While pool cleaners are helpful, they’re not perfect.

Many automatic pool cleaners push debris and algae via a mesh net but don’t remove it from the pool. The mesh bag will clog with gunk and algae fast, and then the goop will launch around your pool.

Tackling the problem in that way is like dealing with an ant infestation by kicking over the anthills. With a robotic pool cleaner, you’re only spreading the problem around.


The simple solution is probably not what you want to hear:

  1. Clean your pool manually.
  2. Use a manual pool vacuum and brush to clear the pool of debris and algae.
  3. While vacuuming, switch the filter to “waste” mode or remove the drain plug to clear out the algae-filled water.

Also, please don’t use “hacks” to clean your swimming pool. I’ve heard folks try to clean their pools with a Magic Eraser—don’t do it.

Mistake #4: Not Cleaning After Animals Jump in the Water

It’s a no-brainer that you should clean your pool after wild animals jump in it, but you should also clean your pool after your pets cool off in the water. No matter how clean you think your pets are, their fur, for example, can clog up the pool filter. Plus, your dogs and cats carry a lot of germs and bacteria, which will contaminate your pool water.


The solution is simple. While the best thing to do is to prevent animals from getting in at all, if your pets still use your pool, just make sure to clean up afterward. This means skimming the pool water for any hair, backwashing the filter if necessary, and topping up your chlorine or chemical levels if anything is off.

Chemistry and Testing Errors

When it comes to chemicals and testing, there are plenty of mishaps that you can make.

Mistake #5: Not Maintaining Alkalinity and pH Levels

A balanced pH is just as critical for your pool as it is for the health of plants and people. A high pH is acidic, while a low pH is alkaline. Excess of either can be bad news.

A low pH, highly acidic pool sounds like a win since algae and other critters will find it challenging to live in acidic water. However, highly acidic water can harm your equipment.

Acidic water may affect the pool’s heater, solar blanket, vinyl liner, pump and filter, and other devices such as automatic pool cleaners, chemical feeders, and maintenance equipment.


The best practice is a delicate balance of alkalinity and acidity. Even a handful of fallen leaves can throw your pool’s pH out of whack, so check your water pH levels often.

You can adjust your pool’s pH levels with an alkalinity increaser, a pH increaser, and a cocktail of other chemicals available in pool supply stores. Read my guides on how to lower alkalinity levels, raise alkalinity levels and pH levels.

Mistake #6: Not Maintaining the Calcium Hardness of Your Pool Water

Balancing your pool’s calcium hardness is as essential as balancing the pH. Too much calcium can make your water cloudy, but with just the right amount, the hardness will keep your pool clean, safe, and pretty.

Appropriate calcium hardness will help maintain many pool elements, like fiberglass, concrete, plaster, filters, and vinyl liners.


Suppose your pool is a bit too soft. In that case, you can mix some calcium hardness increaser into the water, bringing the calcium hardness to the recommended range of 175 to 225 parts per million (ppm). Note: The recommended levels for plaster and concrete pools are 200 to 275 ppm.

Add the calcium hardness increaser when you open the pool for the season. Check the levels regularly, as evaporation and splashing water can lower your calcium levels below ideal.

If you’re using calcium hypochlorite shock, you’re already adding some calcium to your pool, which is excellent for extending the pool equipment’s life.

Mistake #7: Failing to Test Your Pool Water Weekly

Owning a pool is a huge privilege, and testing your pool’s water weekly should be seen as a sacred ritual rather than a chore, so don’t skip it! Stay on top of issues while they’re still manageable and affordable by testing at least once per week.


I recommend testing your pool at least once per week using a liquid test kit or test strips. You should check your pH, alkalinity, and free chlorine levels each week, as these are the most critical elements of clean, safe pool water.

Bring your pool water sample to the nearest pool supply store for in-depth analysis at least once per month.

The primary levels you’re testing for are:

Taylor High Range Swimming Pool Test Kit

This expansive test kit includes nine tests for most pool chemical measurements you need.

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I may earn a commission if you make a purchase, at zero additional cost to you. This in no way impacts my research process or opinions.

Mistake #8: Thinking a Strong Chlorine Smell Means Your Pool Has Too Much Chlorine

If you smell chlorine, it means your pool needs more chlorine, not less. When contaminants in your pool are oxidized, they create chloramines, which give off a chlorine smell. This is a common misconception, which I cover fully in my article on how to lower chlorine levels in your pool.


If you smell chlorine, test your pool’s chlorine level and add more chlorine until the water gives a reading between 3 and 5 ppm. There are a few different types of chlorine; read my guide on liquid chlorine vs. granular shock to learn about a couple of them.

Mistake #9: Not Adding Winterizing Chemicals When You Close Your Pool

When shutting down the pool for the cold seasons, it’s critical to balance the water chemistry. While the pool is closed, algae can accumulate and spoil the water.

Also, if you don’t add a metal sequestrant, you may end up with metal staining.


When you close your pool, add algaecide to control algae growth. Include metal sequestrant to manage metal staining and apply enzymes to protect your pool from organic staining and line scum.

Mistake #10: Not Wearing Proper Protective Gear When Handling Chemicals

It’s important to keep yourself safe. You are handling chemicals, after all! These chemicals can be incredibly dangerous on bare skin, and you shouldn’t breathe them in, either.


Wear proper protective gear from head to toe. Tie your hair up, wear goggles, a mask, long sleeves, and closed-toe shoes. The last thing you want is for a chemical to splash onto your bare skin – especially when you handle harsh chemicals like chlorine or muriatic acid. And in case of any splashes, wear something you don’t mind getting bleached or ruined.

Your Pool Filter

Here are the most common mistakes to look out for with your pool filter system.

Mistake #11: Running Your Pool Filtration System Less Than Eight Hours Daily

What good is a pool’s filtration system if you never use it? The more often you run the filter, the fewer bugs and gunk you’ll have to remove later.


Turn on your pool filter and pump for at least eight hours a day (any less, and you won’t see much progress). Larger pools may need more time than that, but eight hours should be enough for all water to circulate through the filter system.

Mistake #12: Not Cleaning Your Pool Filter Often Enough

If you don’t clean the pool filter often enough, it can wear down your equipment faster. The filter will clog and increase PSI, making it less effective and putting too much pressure on the pump.


Replace sand filters every three to six months and change your filter cartridge every six to 24 months. If the filter is too damaged, you may need to replace it. For specific recommendations, read my research on the best inground and above ground pool filters.

Shocking Your Pool

Watch out for these common mistakes when handling pool shock.

Mistake #13: Adding Pool Shock Into Your Skimmer (Never Do This)

Making the mistake of adding shock chemicals to a skimmer can cause your pool’s filter system to explode!

What happens when you combine chlorine and calcium hypochlorite pool shock? You get a toxic gas. Automatic chlorinators add chlorine to your filtration system. When you put shock chemicals in there, the shock combines with the chlorine and develops deadly gas in a tight space.


Make sure your shock chemicals and skimmer are far apart. Add shock according to the manufacturer’s directions, and always wear proper safety gear.

Mistake #14: Adding Shock Directly Into Your Pool Water

Adding too much “pool shock,” mainly concentrated chlorine, directly into your pool will bleach anything you put inside the pool. The shock chemicals can ruin clothing, for example. If the chlorine concentration is too high in your pool, it may turn white clothes yellow or black clothes pink.

Luckily, while too much chlorine can ruin fabric colors, you cannot over-shock your pool. But there’s one exception: adding shock directly to a pool with a vinyl liner can destroy the liner. The granules of chlorine will seep into your pool liner. The bleached liner will become brittle and weak, causing it to leak.


Protect your pool liner by pre-dissolving the shock chemicals in a separate container, like a bucket. Once the chemicals have spread evenly in the container, you can safely add the mixture to your pool.

Always fill your container with water before adding the chemicals to avoid splashback. Trust me; you don’t want that stuff on your clothes, and definitely not in your eyes.

Using warm water will allow the shock to dissolve more quickly. However, you’ll need protective eyewear, a chemical mask, and chemical-resistant gloves. In truth, these precautions are necessary even when using cold water in your prep bucket.

If any shock (calcium hypochlorite) settles to the bottom of your pool, use a brush to disperse the chemical evenly.

Mistake #15: Shocking Your Swimming Pool in the Daytime

When chlorine attaches to particles in the water, it leaves traces of chemical compounds called chloramines. Because these compounds irritate the eyes and skin, you don’t want that stuff floating around in your pool. This is where pool shock comes in – it helps to keep your pool clean.

The rub is that shock chemicals include unstabilized chlorine, and the sun’s radiation will burn away 1 ppm per hour. The result is a diluted chemical mix, less effective cleaning, and a significant drain on your finances.


To give your pool time to stabilize:

  1. Shock at night.
  2. Shock your pool at least once per week, using roughly one pound (.5 kg) of shock chemicals per 10,000 gallons (37,854 L) of water.
  3. Test and add more shock until the pool reaches the target of three ppm.

Mistake #16: Not Shocking Your Pool Once a Week

It doesn’t matter how well you maintain your pool. If your pool is getting any use at all, you must do your best to keep the water clean and healthy for swimming. And part of keeping the pool clean means shocking the pool once a week.

Regularly shocking your pool will eliminate chloramines, knocking your pool’s chlorine levels down to a safe and pleasant three parts per million (ppm).


Of course, the solution is to shock your pool once a week! In fact, in some cases, you may need to shock your pool more often. Specifically, shock your pool after heavy rain, heavy usage, and other factors that may cause the contaminants in the pool to rise (such as a toilet accident).

Final Mistakes to Avoid

Home stretch! Avoid these mistakes, too.

Mistake #17: Wearing Street Clothes in the Water

I know we’ve all had that moment after too many martinis when all our friends are egging us on: “Do it, jump in! It’s just clothing; who cares? We’ll hold your phone and wallet!”

Ok, just once, for the YOLO memories, if you must. But never rock your streetwear in the pool for long periods, as it floods your pool with all sorts of contaminants that can throw off the water’s chemical balance. Also, the pool water could ruin your clothes.


Wear a swimsuit in the pool. Besides, plenty of fashionable swimwear is out there if you know where to shop. And always rinse off your swimsuit before you jump in.

Mistake #18: Neglecting to Service Your Pool Heater or Pump

If your heater breaks, your pool will be cold year-round. When the pump malfunctions, the pool’s entire system also shuts down. Neither of these outcomes is desirable.

Your pool pump and heater are among your pool’s most heavily used parts, so they wear down quicker. Look out for warning signs like loud noises in your pump or low performance.


Service your pool equipment at least once a year for top performance and significant savings.

Mistake #19: Neglecting Your Pool Water Level

Don’t underestimate how important your pool water level is. It may seem like such a small thing, but if it’s too high, you’ll get water on your pool deck, and your water won’t be properly cleaned. And if it’s too low, your pump may start drawing in air instead of water, which can be dangerous and harmful for the pump!


Always check the water level. The water should be around halfway up the skimmer opening – no more, no less. If you are tired of constantly topping up your water level, you can try using a pool cover to help prevent evaporation. You can also use an automatic pool water leveler.

Mistake #20: Draining the Pool

Sometimes, draining the pool is inevitable. But if you can, avoid it!

Most issues can be solved with water in your pool, including plaster repair. Draining the pool can lead to some pretty expensive and horrible issues down the line, such as your entire pool popping up from the ground or the plaster becoming cracked, as it’s meant to be constantly underwater! Not to mention the sheer expense of refilling an entire pool with water and chemicals once again.


Avoid draining the pool if possible. But if you must, do so under the watchful eye of a professional. They can best guide you on draining your pool without damaging your expensive investment. If you really want to DIY this process, I’ve got a guide on how to drain your pool.

Get My Free Pool Care Checklist

Download my free, printable pool maintenance checklist to help you accomplish regular pool care tasks for any type of swimming pool.

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Have Fun, and Don’t Overthink Pool Care

We’re all bound to make mistakes, and some disasters (like your neighbor’s kid stopping a few yards short of the toilet while swimming in your pool) may occur. You get a pass, as you’re human, and water chemistry can get wonky. But you can stay ten steps ahead of disaster by reading instructions and care manuals, watching online tutorials, and saving this guide in your bookmarks folder.

Have more questions about pool maintenance? Let me know!

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