Hey there, fellow pool owner!
I'll get straight to the point: this is the most comprehensive beginner's guide to pool maintenance that you'll find online.
I created this guide so that even if your just installed a pool, you could use this as your instruction manual.
After all, there are definitely some tasks required to maintain a pool don’t exactly require a professional, so why not save a little money that could be better spent on sunscreen and inflatable floaties?
I’ve divided the guide into chapters so that you can quickly find whatever you need without having to go back and read the whole thing. So if you’re ready to get started, let’s dive in (I love that pun).
Table of Contents
The Ultimate Beginner's Guide to Pool Care
Chapter 1:How To 80/20 Your Pool Care
Chapter 2: Understanding How Your Pool Is Built
Chapter 3:Promoting Good Pool Circulation
Chapter 4: Understanding Your Filtering System
Chapter 6: Pool Chemistry For Dummies
Chapter 7: Troubleshooting Common Issues
Chapter 1:How To 80/20 Your Pool Care
The 80/20 rule says that 80% of your results come from 20% of your efforts.
In other words, in almost every situation, find the effort that gives you the most output and concentrate on that.
Basically what I’m trying to say is that most people will never be experts on every single aspect of pool care, but as long as you have some ‘nuts and bolts’ knowledge and nail down the basics, you'll do fine.
Don’t sweat the small stuff and all that, right?
If you’re reading this guide, you’re probably interested in becoming a halfway decent pool owner, so let me give you just a few tips you might find helpful.
5 Steps To Becoming A Better Pool Owner
Find Your Inner Swimmer
Remember why you wanted a pool in the first place?
It probably started when you were a kid, going to pool parties at your friend’s house and declaring that someday you too would own a pool.
Was it for status? Okay, maybe a little, but more than that, it was about fun.
When you had this pool installed, you were probably imagining all those hot days that your kids would spend splashing around with their friends, filling your backyard with noise and laughter.
Or you imagined the pool parties you would have, grilling out and eating poolside with your neighbors and friends.
Don’t lose that.
On days when your water is cloudy and you’re ankle-deep in algae and leaves, you'll need to remember why you’re still cleaning this thing and not filling it in with cement.
Accept the Challenges of the Job
Remember when your first boss called and offered you a job that you weren’t sure you really wanted to take?
Well, this may be a lot like this.
Let’s face it—scrubbing concrete and cleaning filters isn’t all that glamorous, but they are jobs that have to be done.
So, you may as well buck up, take the job and make the commitment to show up for work.
Once you have a routine, it’s really not that hard, and you might even end up enjoying it!
I’m not gonna lie—when your daughter’s friends are slopping on more sunscreen than they need and wading in the shallow end with their popsicles, it’s really hard not to get aggravated.
You did, after all, spend two hours cleaning the pool last Sunday.
But remember what I said in tip #1?
Remember why you wanted a pool!
Was it so your family could enjoy it, or so that you could have a sparkling clear body of water shimmering in your backyard?
If you did it for fun, lighten up and remember you'll be cleaning it again on Sunday no matter what. So, let them enjoy it.
Otherwise it will become a source of contention for the whole family.
Let the Kids Help
We're always looking for teachable moments for our kids, right?
So, instead of taking the whole job on yourself, let your kids know up front that this is a family affair.
If they want to enjoy the benefits of the pool, then they have to share in the responsibility. Sure, eight years old is probably too young to handle the chemicals, but you can teach him to use the pool vacuum or skim the leaves out every day.
If they feel invested in the project, they’ll be more likely to keep it clean.
This is probably the best piece of advice you'll ever get from me:
Do not let a month go by without checking your pool chemistry levels.
Do not let a week go by without skimming it out after a rainfall.
And do not let even a day go by if you are starting to notice significant algae blooms.
The better you stay on top of keeping your pool clean, the less work it will be for you on a weekly basis!
Chapter 2: Understanding How Your Pool Is Built
Knowing just a little bit about your pool components and how they work will help you understand why you do certain things in maintaining it.
It will also help you to better understand when a pool problem is chemical related or system related.
First of all, there are several types of pools and they are each constructed a little differently.
The 5 Types Of Swimming Pools
Here are the different types of swimming pools you should know about.
1. Concrete Pools
Concrete pools are what you probably think of when you think of inground pools, but they're actually not the most popular (we’ll get to that next).
These pools are built by digging a hole in the ground (don’t try to do this yourself), and then assembling the plumbing and framework inside the hole.
The framework is usually constructed with rebar (steel reinforcing rods) in a grid-like pattern. Then they pour concrete into forms and constructed inside the rebar grid.
2. Gunite Pools
You may never have heard of gunite pools, but they're actually the most common pools built in the U.S.
They're constructed pretty much the same way as concrete pools, but the gunite is sprayed into place and then troweled to smooth it out. After it dries for several days, they then apply a finish to or paint it.
Gunite is a mixture of cement and sand and is used more than concrete because it’s a little easier to work with.
It’s also very durable and can be finished in a variety of different mediums, such as tile or fiberglass, making it a highly versatile option.
3. Fiberglass Pools
Fiberglass pools are constructed from a plastic that is reinforced with fiberglass and molded into its pool shape.
These are installed in holes dug in the ground as well, but the shape of the pool is already formed before it even arrives.
The plumbing is put in before the pool is set and hooked up once the pool is lowered in.
4. Vinyl Inground Pools
Vinyl inground pools are constructed with a frame of wood, plastic or metal inside a hole dug in the ground—sand is then poured along the bottom and as filler.
The vinyl liner is then secured into place to fit the shape of the formed construction.
5. Above-Ground Pools
Most above-ground pools are constructed in a factory or assembled in kits for the pool owner to put together themselves.
But even though they're easier to build, they still require leveling with sand and plumbing that has to be laid.
Once the frame has been constructed, the vinyl liner is smoothed into place and secured with the rim or fasteners.
The 7 Major Components Of A Pool You Need To Know
No matter which type of pool you have, it should be designed with some type of filtration system to keep the water circulating and debris skimmed off as much as possible.
Some pools are also installed with optional heating systems to keep the water warm, but aside from that, most pools operate basically the same and have these basic components:
A pool pump is a system with an electric motor that pushes water from the drains to the filter and then back out the returns.
A pool usually has one filter, but some have two, and there are different types: sand filters, DE (Diatomaceous Earth) filters, and cartridge filters.
But they all accomplish the same task: they clean the water the pump pushes into them from the pool drains and release it back through the returns to re-enter the pool.
Your pool’s drainage system will usually be composed of 2-3 main drains at the bottom and several skimmer drains around the surface edges.
They're designed so that debris will sink to the bottom and be sucked into the drains, much like your bath water does when you pull the stopper: except the suction isn’t usually as strong because they are covered with covers specifically designed to prevent a vortex.
Skimmers are smaller drains around the edge of the pool where the water surfaces. They work like the drains, but skim out matter that is floating before it sinks.
Returns are valves around the edges of the pool. They get the water after it is sucked through the drains and passed through the filtration system.
6. Chemical Feeder
A chemical feeder or pool chlorinator is technically an optional piece of equipment you can install so that chlorine is released into your pool periodically instead of all at once.
Automatic feeders can be installed in the filtration system so that the chemicals circulate with the water.
A more common type of feeder is a floater: a floating device that you can add chlorine tablets to so that the water washes over them and chlorine is released more slowly.
A pool heater is another optional component that comes in gas, propane, electric, or solar models.
Each of them work a little differently, but basically warm water as it is circulated from the pump and then feeds it back through the returns.
Chapter 3:Promoting Good Pool Circulation
All those components we just talked about are designed to keep your water circulating, but you also need to do a few things to help the process along.
Sounds like extra work, I know, but the problem is there are usually certain spots in the pool that don’t get much movement.
Also, if the filters get clogged even a little bit, your filtration system could lose suction, hindering the whole process.
So how do you keep that water moving like you just gave it Ex-Lax? By taking these few precautions:
5 Steps To Achieving Ideal Pool Circulation
1. Beware Of Dead Areas
Certain areas in the pool are harder to get water moving through than others, making them dead areas or dead zones. These areas are commonly right by the skimmers, in the corners, and behind the ladder.
So, to address the problem, you need to position your returns down so that water will circulate more thoroughly around the bottom and corners.
You can also put special fittings on your returns that rotate to hit all the areas around them.
2. Keep the Filter Clean
Dirty filters mean slow moving water.
And, they don’t just get clogged with leaves and debris: calcium buildup can also be a problem.
That’s why you need to properly clean your filters regularly.
Sand and DE filters will have to be backwashed, and cartridges will have to be removed and hosed off.
3. Brush and Vacuum
Because you probably won’t be able to completely bring the dead areas back to life, you'll need to regularly brush the surface of the pool.
Pay special attention to the dead zones we talked about and then run the vacuum.
This not only circulates the water while you’re doing it, it also keeps debris from gathering harmful bacteria.
4. Swim in It
Sounds simple enough, but when you use it for its intended purpose, you'll naturally keep the water stirred up and moving around.
5. Run Your Pump
Your pool has a filtration system for a reason, and none of the other steps will make much difference if you don’t use it.
The pool pump is what keeps the water constantly moving and skimming out debris.
Run it a minimum of 8 hours a day, longer during times of heavy use.
Chapter 4: Understanding Your Filtering System
Understanding a little bit about your pool’s filtration system will help you better care and maintain it.
The pool filter is the component that cleans the water as it passes through from the drains and then pushed back into the pool through the return outlets.
There are three different types of pool filters and each one works a little differently.
The 3 Types Of Pool Filters
1. Sand Filter
A sand filter is one of the oldest types of filters available, but still a good option for most pool owners.
These types of filters are equipped with tanks that are kept filled with a sand product made especially for pools.
The water travels from the drain through the tank of sand to clean and filter the water as it passes through on its way back to the pump and out the returns.
Sand filters have to be backwashed regularly as a way of keeping them clean.
2. DE Filter
A DE filter works pretty much like the sand filter except that it uses “fingers” coated with DE powder to filter the water as it passes through.
Note: DE filters have to be backwashed also.
3. Cartridge Filter
A cartridge filter comes in models that use either a single or multiple cartridges that are usually made out of plastic tubes with accordian-folded polyester/fiberglass fabric wrapped around the core.
These folds of fabric are what catch dirt and debris as the water passes through.
Cartridge filters are easier to clean than sand or DE filters: you simply replace the cartridges as needed.
How To Choose Your Pool Filter
Each type of pool filter will effectively clean your water, so how do you know which one to choose?
Well, the decision usually boils down to a couple of factors: cost and maintenance.
A sand filter will probably last longer than the other types and it is relatively low-maintenance. You also only need to refill the sand once every few years so the cost of maintenance is low.
A DE filter is shown to be the most effective filter for cleaning out dirt and small debris, but it is a little more difficult and expensive to maintain. It also may not last as long as a sand filter.
The cartridge filter is the easiest to maintain, which is why many people choose this one. Simply toss out the old cartridge and replace it with the new. It's also more energy efficient than the others. However, it too is a little more expensive and difficult to maintain.
The best way to choose your filter is to figure out which quality is the most important for you and narrow down your choices.
Do you require the purest water, the lowest maintenance, or the cheapest price?
Any of them you choose will keep your water clean, so don’t let the options overwhelm you.
Chapter 5: DIY Pool Cleaning & Maintenance
When it’s feasible, doing your own pool maintenance and cleaning can save you thousands of dollars a year.
And with the right information, it's nothing you can’t learn to manage on your own.
But it’s important to realize that occasionally, you might still have to hire someone.
For example, if your pool comes down with a major case of black algae that you can’t seem to get rid of.
Or if your plumbing needs repair.
It’s okay to hire a pro for major issues, even if you decide to handle the day-to-day upkeep yourself.
And assuming you’ve decided to be your own pool guy, there are just a few pieces of equipment you just can’t do without.
6 Pieces Of Pool Maintenance Gear Every Pool Owner Should Have
While owning a pool is a lot of work, the truth is that there aren't that may pieces of equipment you need to buy.
1. Automatic Vacuum
An automatic vacuum won’t completely eliminate your need for a manual vacuum, but it will save you tons of time and energy when it comes time to clean out your pool.
Automatic vacuums connect to your pool’s system in one of three different ways and the movement of the water pushes it along the surface while it sucks up debris.
Suction-side cleaners are automatic vacuums that connect to the suction side of the plumbing.
It uses the pressure of the suction to move it along the surface, and then pumps the mess through its hose into the skimmer baskets. Most of these are used for dirt and microscopic particles, while leaves and larger debris still need to be skimmed out manually.
Pressure-side cleaners uses the pressure side of the plumbing to move it along the surface.
These are typically equipped with their own debris bags so that they cut down on the strain to the pool’s pump and filter system.
They also require a little less work since you can dump out the bag occasionally instead of having to spend so much time cleaning all the skimmer baskets. These are best for clearing out leaves and larger debris.
Robotic cleaners are connected to your pool’s GFCI outlet so they move along the bottom and even up the sides of the pool regardless of the current of the water.
They also have their own debris bag so it frees up the pump and filter system on your pool.
Overall, these are the most convenient and effective cleaners, but they can also be more expensive.
2. Vacuum Head
A vacuum head is part of the manual vacuum system you'll probably still need to use from time to time.
You’ll connect the vacuum head to a telescope pole and then to a vacuum hose and the whole system is then attached to the skimmer.
If you simply don’t want to buy an automatic vacuum, this one will do the job. You'll just have to use it a lot more often.
3. Vacuum Hose
The vacuum hose will serve as the connector between the vacuum head and the skimmer.
It helps contain the suction that cleans out the debris.
4. Pool Brush
A pool brush is an important part of pool maintenance since there is some debris, such as algae, that clings to the surface of the pool and can only be removed by force.
A pool brush usually connects to the same telescopic pole you use for the vacuum. There are different pool brushes made with different materials, and the one you choose will depend on the type of pool you have. Their bristles are usually made of steel, nylon or a combination.
Steel-bristles brushes should only be used on gunite or unpainted concrete. These are particularly useful when you have a severe algae problem that you can’t get a handle on.
Nylon brushes can be used with all pool types and they are the only kind you should use for fiberglass or nylon pools so that you don’t damage the surface.
Combination brushes that are nylon and steel mixed should also only be used on gunite or unpainted concrete.
5. Skimmer Net
A skimmer net is designed to attach to a telescopic pole so you can reach all areas of a large pool.
It's what you'll use to skim out debris floating in the pool such as leaves and bugs.
6. Telescopic Pole
The telescopic pole is the pole we speak of.
It's what you'll connect all your tools to to give you a farther reach when brushing, vacuuming or manually skimming.
Cleaning & Maintenance Tips
There's a lot of work and knowledge that goes into keeping your pool clean—here are my top tips for maintaining your pool and gear.
Quick Tips for Vacuuming & Brushing Your Pool
- Always skim out as much debris as you can manually before you begin vacuuming to save wear and tear and clogging of your unit. This will also keep you from having to clean out the vacuum’s debris bag or your skimmer baskets as frequently.
- Vacuum your pool at least once a week to keep it clean and algae-free.
- Brush your pool before you vacuum to loosen up debris or algae spores, making it easier for the vacuum to remove.
- Always hose off the vacuum after use to prevent algae from growing on and inside it.
- Make sure you use the proper pool brush for your type of pool. Never use steel bristles to clean a vinyl or fiberglass pool or you'll damage the surface.
- Brush your pool every time you vacuum, at least once a week.
- Be sure to thoroughly brush around and behind skimmers, lights and ladder fittings, as these are the places algae tends to lurk.
Quick Tips for Chemically Cleaning Your Filter
Once in a while, your filter may get a buildup of calcium deposits or grime from natural oils (like from skin and sunscreen).
You might start to notice that even with a new cartridge or clean sand in your filter, it just doesn’t seem to be working quite as well as it used to. Or you are having to replace it every few days.
When this happens, inspect your filter carefully. You'll be able to see whether or not it needs to be cleaned.
Most of the time, the components can be cleaned by hosing them off really well, but if that doesn’t work, you may have to use chemicals specially designed for this purpose.
- For cartridge filters, use a solution of TSP and water in a bucket to soak them in overnight. Then rinse off with high-pressure hose the next morning.
- Always wear safety goggles and rubber gloves when handling chemicals.
- Sand filters and DE filters should only be cleaned with cleaners made especially for them.
- To clean sand and DE filters, you'll simply add the chemical to the filter during the backwashing process.
- Always thoroughly rinse your filters after chemically cleaning.
Quick Tips for Cleaning Solar Blankets & Winter Covers
- Clean your pool cover once per year (more if needed).
- The best cover cleaner is a mild dish detergent and water solution sprayed all over the cover.
- Use a soft pool brush to gently scrub the pool cover.
- Rinse the cover thoroughly with a high-pressure hose.
- Use a pool cover pump for solid winter covers to remove standing water.
Chapter 6: Pool Chemistry For Dummies
Maintaining the right pool chemistry could very well be the most important job a pool owner has.
Because if the levels are kept within range, you'll have a lot less problems keeping it clean and keeping algae from growing.
Now, wouldn’t you like to have a trouble-free pool?
You might be thinking that all this chemistry talk sounds a little overwhelming, but it’s really not that difficult.
In fact, most of the pool chemistry testing products you buy make things pretty foolproof. But you know what?
If you do have an aversion to testing the chemicals, you can always just take a sample to your local pool supply store and let them test it for you.
But if you want to give it a try yourself, purchase a pool testing kit, either with chemicals or strips and let’s get started...
6 Pool Chemistry Terms To Know
When you're reading up on pool chemistry, you'll start to see there are certain terms that are thrown around often, so it's good to familiarize yourself with them so you can follow along.
1. pH Balance
The pH level is what measures the acidity of your pool water.
If your pH levels get too low (below 7.4), the water is too acidic. If they're too high (more than 7.6), they're too basic.
>>Read: How to lower pH in your pool
Levels that are out of balance in either direction can cause issues like skin and eye irritation, pool liner and equipment erosion, scaling and ineffective chlorine.
The ideal pH range is between 7.4 and 7.6.
If your test determines the levels are out of range, use sodium carbonate or sodium bicarbonate (baking soda) to raise it, or use muriatic acid or sodium bisulfate to lower it.
You'll be able to purchase these items at your pool store or online and they will usually be called pH reducers or pH raisers.
They will also give you complete instructions on how much product to add and how to distribute it.
pH balance is an unstable factor, so it needs a moderator, which is what alkalinity is.
If you keep this level balanced, your pH levels will be more likely to stay within range.
The ideal alkalinity level is between 100 and 150 ppm.
Usually if there is a problem with alkalinity, it is that it is too low.
Sodium bicarbonate (baking soda) is the best chemical to regulate it; it's usually just sprinkled around the edge of the pool, but if you buy the bags especially packaged for swimming pools, it will come with complete instructions for use.
3. Calcium Hardness
Calcium hardness is what determines how hard or soft your water is.
If your water is too soft, it will feel slimy and dirty. It can also cause corrosion to your pool’s surface. But if your water is too hard, it will cause scaling on pool equipment and become cloudy.
The ideal level for calcium hardness is 150-400 ppm.
In order to raise the calcium hardness level should it test too low, add muriatic acid according to the manufacturer’s instructions.
To raise it, add calcium chloride.
4. Sanitization (& Chlorine)
Sanitization is the most important part of pool care since it is what fights off germs and algae that make your water dirty and unhealthy.
Chlorine is the most common chemical used to sanitize pools because it is simply the most effective, but some people choose to use other products such as biguanide, bromine, or mineral systems for various reasons.
Chlorine comes in liquid, granule, or chemical form. They all do the same job but have different application methods.
Ideal chlorine levels are 2.0-4.0 ppm (parts per million).
5. Pool Shock
You've probably heard people say you need to “shock your pool.” And all that means is that you're going to super chlorinate it at shocking levels.
Shocking your pool on a regular basis (about once a week) will help kill off any bacteria or algae hanging around that your regular chlorine levels aren’t killing. It also helps the chlorine you keep in your pool daily to be more effective.
Pool shock is also the name of the actual product you'll buy to perform the process and they all come with their own instructions.
There are some non-chlorine products on the market buy they don’t work quite as effectively and absolutely will not work if you have a major algae problem.
But if you don’t have an algae problem and wish to continue swimming pretty soon after treatment, then a non-chlorine shock might be a good product to use occasionally.
6. Algae Control
Most algae is not harmful to humans, but some do produce toxins.
However, even the algae that isn’t harmful will muck up the water and harbor bacteria that can be harmful. It also throws of your pool chemistry balance, making it more difficult to clean and sanitize.
There are three main types of algae commonly found in pools—green, black and yellow—but there are literally hundreds of other species on the planet.
Chlorine is the only chemical known to completely eradicate it, but a good algaecide can help you control it.
Chapter 7: Troubleshooting Common Issues
No matter how hard you work to keep your pool clean and trouble-free, there will occasionally be some problems that pop up that you'll need to deal with.
And as annoying as it can be, it’s important to deal with them soon so that they don’t become an even bigger problem.
Smart Tips to Contending with 6 Common Pool Issues
While there are dozens of issues that could give you trouble with your pool, here are six of the most common you should be familiar with.
1. Cloudy Pool Water
If you have cloudy pool water, first you'll need to figure out what is causing the pool water to be murky, and testing the pool chemistry is a good place to start.
If any of the levels are off, they can cause cloudy water for various reasons. Get those levels balanced.
If that doesn’t fix the problem, check your filters.
If they are clogged or the pump isn’t running right, they won’t be cleaning the water like they should. If your filters need to be cleaned, hose them off well and use the appropriate chemicals when necessary.
If you're having regular issues with cloudy water, but everything seems to be working right and your chemicals are balanced, you might need to use a pool clarifier every week after cleaning.
This product will clump tiny particles of debris together so they can be more easily filtered out.
Algae can usually be controlled by consistently shocking your pool.
You'll also need to use a pool brush to scrub the surface so that you are removing any algae spores from the sides that you might not be able to see. Using an algaecide after shocking the pool is also key to keeping it under control.
But if you are still having problems with it, you may need to double shock your pool, brushing and vacuuming after each treatment.
If you're still unable to remove the algae yourself, you'll need to call in a professional as soon as you can to get it under control.
Large black algae infestations sometimes require the pool be completely drained and scrubbed to eradicate it. (Read: how to drain an above ground pool).
3. Green Pool Water
Green pool water is simply an indication that it has been taken over by algae and you'll have to follow the proper steps to remove it.
Brushing, cleaning and shocking will be required, possibly over several days to clean it up.
4. Pool Foam
A foamy pool can be caused by several things—cheap chemicals, shampoos or other personal hygiene products, too much algaecide or other chemicals, or plumbing problems.
To fix the problem, you'll need to figure out what's causing it.
First, check the algaecide you are using and make sure it says on the label that it is “non-foaming.” If not, that may be your culprit.
Scoop as much foam from the pool as possible with your skimmer and discontinue use of the product until you can buy some that is actually non-foaming.
If the problem stems from the products people are wearing to the pool, make sure you tell everyone to rinse off quickly in the shower before entering the pool.
If this fixes it, you may be able to narrow down the product to a specific lotion or other product someone is using.
You should also check your pool’s chemistry. Almost every pool problem can be solved by balancing its chemistry, so make sure all your levels are in check.
If none of these things seem to help, check for tears in the pool lining or damage to your return jet fittings. The foam could be caused by leaks that are bubbling to the surface.
Stains in your pool can be caused by all kinds of things, but you'll probably need to find out what's causing it to properly remove and prevent them.
Brownish stains, for example, are often caused by metal found in your water supply. You may not be able to completely prevent them, but you can usually remove them if you act quickly. Try adding an acidic citrus-based cleaner directly to the stain and scrubbing it with a brush.
If the stains are caused by algae or other debris, such as berries or other organic matter, you should probably be able to easily remove it by putting chlorine directly onto it and scrubbing it.
For large stains or stains that are in too many areas to scrub individually, you might try doing a complete brushing and shocking in addition to your regularly scheduled days.
If your pool is leaking on the outside, you'll be able to see the water running from it, so those are easy to detect and figure out how to fix. If it looks like it is coming from the plumbing, it could be a cracked pipe and you’ll require a professional to fix it.
If, however, you think your pool is leaking somewhere inside, that’s a different story.
First of all, make sure that you're not just losing water due to evaporation. The best way to test this is by using the bucket method.
For the bucket method, you'll set a 5-gallon bucket on one of the steps of your pool and fill it with water at the exact level of your pool water. Use a sharpie to mark the water line and check it in 24 hours. If the pool and the bucket have both drained to the same levels, the problem is just evaporation.
If not, then you have a bigger problem. To find the leak, first look around with your pump running to see if you find any bubbles coming up from around fixtures or jet fittings. If so, check the area to see if you need to replace any of them.
If you can’t find it that way, you can use some leak finding dye that comes with droppers.
Squirt it in small amounts in those same common places for leaks. If there is a tear in the lining, the dye will gravitate toward it. If you can’t find it immediately, put on pool goggles and inspect the pool thoroughly everywhere, looking for tears or small rips.
When you find the leak, you can use a pool vinyl repair kit to fix it. If you have trouble finding it yourself, you might have to call a professional or completely drain the pool to inspect it better.