13 Common Pool Maintenance Mistakes and How to Prevent Them

Proper pool maintenance has to be learned, and even tiny mistakes harm the water quality. But which mistakes should you avoid in your swimming pool, and which pool maintenance tips actually work?

The filter system must run at least 6 hours/day when it comes to pool maintenance. The pool water is tested regularly, and disinfectants like chlorine are used. You should also set up bathing rules such as showering before using the pool and prohibit bathing in street clothes.

It is shocking how much half-knowledge is published in forums and other websites about pool care. So here are the most common mistakes you should avoid when looking after your pool.

1. The pool is not scrubbed regularly

Many beginners are often told that an extended filter run time and an extra shot of pool chemicals are the only solutions when the pool water becomes cloudy.

But that only causes additional costs and harms the environment.

This statement is not uncommon for a salesperson who sells his pool stuff.

Based on the statement, many beginners neglect manual pool cleaning, and various deposits such as algae or germs settle that cannot be removed with normal filtration.

The deposits then sooner or later lead to cloudy and milky pool water.

The solution: The pool has to be cleaned manually at regular intervals. This includes scrubbing the surfaces with a brush – weekly use is the minimum.

Proper pool maintenance is usually the simplest, and it is not always necessary to use chemicals.

In most cases, a pool brush is sufficient to remove deposits and prevent cloudy pool water in the long term.

Make sure you scrub all corners, walls, and stairs with the brush thoroughly. Pool ladders should also be cleaned briefly with the brush.

But that’s not all.

Of course, a correspondingly long filter runtime is required. Learn more about the filter run times in the next chapter.

2. The filter system runs less than 6 hours a day

New pool owners try to save electricity with pool maintenance and let the filter system run for less than 6 hours a day.

However, here are savings made in the wrong place, and in most cases, the result is a green pool.

Furthermore, the subsequent costs – for chemicals and filter running times – far exceed the savings achieved.

Therefore, the filter system in your swimming pool should run for 6 to 8 hours a day. The running times will be adjusted upwards accordingly if the pool is used more.

A shorter running time of the filters can be useful, but not in the summer with over 90 °F.

The high temperatures encourage algae growth in your pool.

If the water in your pool is not circulated at least once a day, the pool water will tip over and the green pool already mentioned will appear.

The solution: Optimized filter run times so that the water stays clean:

Season Runtime in hours
Spring 2×2/day
Summer 2×4/day
Autumn 2×2/day
Winter 2×1/day

If the electricity costs from the pool pump are too high, then the pump may be oversized or too weak.

Both lead to increased electricity costs for pool maintenance.

In my article on pool pumps, you can use simple methods to check whether you are using the right pool pump. Just click on the link.

3. The sand filter system is backwashed too often

Fine turbid substances are filtered out of the pool water with a sand filter system. That is why the filter system should not be missing in any water treatment system.

To ensure that the filter function remains at a high level, the sand filter system must be cleaned at regular intervals, including backwashing.

Backwashing the sand filter system flushes the accumulated dirt out of the system. This process ensures that the filter sand holds back the dirt flowing through.

Beginners wrongly assume that frequent backwashing improves the functional principle of the sand filter system. It is not uncommon for the system to be backwashed every 2-3 days.

But that’s fundamentally wrong when it comes to maintaining your pool.

A sand filter system should be backwashed every 10 to 14 days.

This is because some of the filter medium is always lost with backwashing. If the filter sand is not refilled in time, the filter performance of the system will suffer.

Many don’t know that the filtered dirt favors the pool water’s filtration by serving as a filter medium to a certain extent.

As a result, the filter medium is less stressed, and changing the sand in the sand filter system can be delayed.

4. Not balancing the alkalinity

The acid capacity (also known as acid-binding capacity or alkalinity) interacts with the pH level. It is decisive for the quality of the pool water.

Many beginners have already heard something about the pH level. Still, especially at the beginning, many neglects the acid consumption in the pool water.

This has a corresponding effect with strong fluctuations in the pH level.

We remember. A high pH level is associated with basic (not acidic) water.

The pH in your pool may be high, and still, too much acid has been added to the water.

But how can there be too much acid when the measured pH is above 8.0?

This is the trap many beginners fall into.

Many measures a high pH above the optimum of 7.2 to 7.6 and recklessly pour more acid into the pool to lower the pH level. But nothing is achieved with this, and the pH level fluctuates wildly and continues to lead to all sorts of problems with pool maintenance.

The reason for this is simple: If the acid capacity is below 80 ppm, then that is an indicator of too much acid in your pool.

The solution: You first have to optimize the acid capacity in your pool before you start balancing the pH level.

The alkalinity in the pool can be optimized with appropriate means.

However, it is important to test your water with the right tools in order to rule out incorrect measurement results. You can find more information on how to test the pool water correctly in my blog.

Tip: Measure the alkalinity in your pool at least once a month to handle the pH level.

5. Ignoring the pH level in the pool water

There are pool owners who control the pH level in the pool rarely, and there are those who ignore the pH level completely.

In the second case, the pool maintenance takes place after a visual assessment of the pool water. Since the pH level increases naturally through filtration, it is often assumed that it is enough to pour some acid into the pool water from time to time.

Both methods are wrong when it comes to properly maintain the pool.

The pH level is one of the most important parameters in your swimming pool. It should not be ignored under any circumstances.

If the pH level is not checked weekly, the entire pool can turn into a green monster within a few hours or overnight.

However, a pH level that is too low is also bad for your pool and the water balance.

The consequences of a low pH are:

  • Torn out joints and expensive renovation work.
  • Damage to the expensive pool equipment.
  • Algae (especially the black algae) and germs nestle in the damaged joints.

Therefore, you should not ignore the pH level under any circumstances – measure and optimize the pH level at least 1-2 times a week.

You can possibly do this with simple test strips.

The test strips are fine for the continuous control of the pH level in a pool. The cuvettes with OTO drops or tablets are more precise and should always be preferred.

But be careful: The test strips can usually only measure up to a pH level of 8.2. The pH reducer will be incorrectly metered if the level is much higher.

Suppose problems with the water balance occur more frequently.

In that case, an electronic water tester is recommended. The E-Tester delivers an exact result and is not limited to the measurement result like the test strips.

6. Optimization of the calcium hardness is forgotten

When we talk about calcium in the pool, we mean optimizing the hardness of the water.

In itself, lime is harmless to humans. Still, it can cause serious damage to the pool and color the pool water milky.

Unfortunately, only very few newcomers are aware of these consequences due to insufficient information.

There is hardly any information on the Internet about the problems caused by limescale in the pool. This may be due, among other things, to the fact that it was previously not possible for a private pool owner to determine the water hardness in the pool.

That is why the topic has received little attention, and supposed advisors don’t know how to handle this problem.

However, preliminary clarification does not mean that only a few pool owners have a problem with limescale edges and calcified sand in the sand filter system.

On the contrary, the forums are piling up with questions for advice on how to fix the problems, all of this only because the optimization of the water hardness in the pool is omitted.

For this reason, you shouldn’t make the same mistake in pool maintenance and worry about the calcium hardness in your swimming pool in addition to the pH level and total alkalinity.

The best way to avoid problems with calcium in swimming pools is to regularly check the calcium hardness with water testers.

Test the calcium level at least once a month. Ideally, the calcium hardness in the pool is between 200 and 400 ppm – an average level of 300 ppm is considered optimal.

Then you can – if necessary – lower or increase the water hardness in the pool with a powder. Both agents are available from specialist retailers.

It is best to use a pH-neutral product and always follow the manufacturer’s instructions when using the agent.

Preventing limescale build-up is always the more rational option for any pool owner, as acid washing takes a lot of time and effort.

Not to mention the environmental pollution and the extra costs involved in removing the lime.

7. Pour chlorine directly into the pool water

A Pool shock in the pool is necessary from time to time in order to remove stubborn cloudiness.

The mistake many beginners make is that the chlorine is poured undiluted into the pool water. This can lead to white spots – also known as bleach marks – and deface the expensive liner.

It would be correct to dilute the chlorine in the bucket beforehand and then shock the pool. You can find out exactly how this works in the linked blog article.

Another mistake that many beginners make when using chlorine: The chlorine tablet or chlorine granulate is dosed via the skimmer.

This is wrong and leads to a reduction in effectiveness up to 20%, which leads to increased chlorine consumption.

The resulting extra costs can be reduced by using chlorine tablets via a floater.

It is best to hang the floater on the return nozzles of your swimming pool with a string – this ensures a better distribution of chlorine.

Floaters should not be used in PVC or vinyl liner because they can cause bleach stains. In this case, you don’t have a choice and should use the chlorine tablets in your skimmer.

Tip: If free chlorine is being produced with a floater, the need for pool shock is reduced. The addition of chlorine is simply increased by adding more chlorine tablets to the floater.

8. The pool shock is done during daytime

One of the biggest mistakes beginners make using pool shock is that the procedure is done in bright sunshine in the middle of the day.

You ask yourself: What speaks against using a pool shock when the weather is nice during the day?

For the pool shock, we need non-stabilized chlorine. This means that chlorine does not contain a stabilizer like cyanuric acid.

Due to the activity of the UV rays, the molecules break down quickly, and chlorine loses its oxidative power. You pour the chlorine into a bottomless barrel, and in the end, it has little or no effect.

But couldn’t you just use a stabilized chlorine for the chlorine shock in the pool?


The chlorine has to work quickly, which is only possible if it is non-stabilized (free chlorine).

The solution: If you perform a pool shock in your pool or whirlpool, this should be done in the late afternoon or evening to protect the chlorine from decomposition by the sun’s UV rays.

If you use chlorine, bromine, or active oxygen instead of chlorine, the time of day is not important. You can read the exact differences in the article on pool chemicals.

9. Combination of different pool disinfectants

A critical mistake many beginners make in pool maintenance is combining different disinfectants.

Maybe you are familiar with this situation.

You use chlorine, but still, you have a problem with the water quality in your pool. Then you search for advice in a forum, and the users recommend a disinfectant that can help solve the problem.

In addition to the chlorine that has already been used, bromine, active oxygen, or biguanide may also be used blindly.

The disinfectants all have an oxidizing effect on germs and other cloudy substances in the bathroom.

The problem is that the individual agents are difficult to combine.

In practice, it has long been known that active oxygen and chlorine cancel each other out. The result is that the desired effect is completely lost, and the pool water balance suffers even more.

Chlorine is cheap and is strong but can lead to side effects if misused. Active oxygen is much more pleasant for bathers, although slightly more expensive than chlorine.

The decision is yours and personal preference.

But remember: Proper pool maintenance is all about using a single disinfectant and avoiding combinations.

Due to the health risks from chlorine, beginners often try to switch to another disinfectant and forget that residues from the old disinfectant negatively affect the oxidizing power of the new agent.

This is the case with biguanide, for example, if the pool has not been thoroughly cleaned beforehand.

A change to another chemical is usually associated with draining your swimming pool. Therefore, think carefully beforehand about which pool disinfectant you want to use for pool maintenance and stick to it.

10. The pool water is tested too infrequently

You now know the most common pool maintenance mistakes that a beginner can make with pool chemicals, and I showed you how to avoid these mistakes.

However, what is rarely mentioned in pool care guides is that the pool water must be regularly checked with suitable water testers.

This is important to stick to the pool chemistry dosing instructions and avoid overdosing.

When testing pool water, you have the choice between:

  • Simple test strips for continuous control.
  • Cuvettes with OTO drops or tablets that are more precise than test strips.
  • Electronic testers where you almost can test all parameters.

With all the methods, you can test the individual parameters in the pool water, but what is not mentioned are the possible errors in the measurement result.

A simple test strip is more likely to produce falsified results. If the parameters are checked too seldom, it can happen quickly that your pool turns green.

Therefore, it is advisable to check the pool water regularly with an electronic water tester.

Of course, you don’t have to test every day the water balance.

Some parameters have to be checked weekly, and others are checked once a month.

In my blog article, you will find an overview of the most important parameters and a precise explanation of how often you have to test the pool water.

11. Use of an automatic pool cleaner for problems with algae

The automatic pool cleaner is useful to keep a large swimming pool permanently clean.

However, many pool owners have too great hopes for these devices.

The misconception has spread that a pool robot against algae alone is sufficient and that the swimming pool can be operated without chlorine.

One thing must be made clear: The pool cleaning robot can remove the deposits caused by algae, but this will not prevent the algae from growing again in the future.

Algae growth in your pool always occurs when the water balance is incorrect.

So if you have problems with algae, you have to use chemical agents such as an algaecide to inhibit algae growth.

The algaecide acts as a preventive measure and is not cleaning a green pool.

Before that, the algae in the swimming pool must be scrubbed and filtered out with the sand filter system. You can find detailed instructions in my blog – click on the link or use the internal search function.

12. Using the pool without a shower before

The shower in the garden is an important accessory to keep your swimming pool clean.

Every swimmer drags huge amounts of fine turbid substances into the pool, which can cloud the water. These include sun creams, perfumes, dander, sweat, urine, and other substances.

We are talking about colloidal impurities that are too fine to be filtered with the sand filter system.

Colloidal substances serve as food for germs and are often the trigger for the unpleasant film of grease and grease edge in your pool.

And yet many bathers miss a quick shower before jumping into the pool.

Taking a quick shower before using the pool is a minute’s act that can save a lot of the hassle and expense of cleaning the pool water.

It is not only the bathers who are to blame. As the pool owner, you are responsible for keeping the pool clean.

It is best to set up a solar shower near your pool and advise all bathers to use the shower.

Make it a bathing rule!

The bathing rule may sound strange, but you will save yourself many uncomfortable hours cleaning your swimming pool.

Anyone who has ever had to remove a fat rim knows what we are talking about.

13. Swimming in the pool with street clothes

It doesn’t really need to be mentioned, but bathing in street clothes is not allowed.

The pool is not a washing machine, and if you want to use the pool, you should do so in swimwear – that would be another bathing rule in addition to the shower.

Unfortunately, many people see it differently, and the pool water becomes cloudy.

Various substances end up in the pool with street clothing, which can upset the balance.

In the worst case, dangerous black algae are brought in because the same bathing suit was used in the quarry pond, and the things were not washed beforehand.

Do you have further questions about pool care and the mistakes?

Contact me on Twitter at @contactswimfool. I am happy to help you.

Good look keeping your pool water clean!

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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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