10 Steps How to Change The Sand in Your Pool Filter System

The sand change in the sand filter system is necessary from a certain point in time so that the pool water remains crystal clear. But when does the filter sand has to be changed, and how often should this happen?

The filter sand is usually changed every 1 – 3 years and, if the sand is more worn, after one year. According to the manufacturer’s instructions, after the water in the filter has been drained and all screw connections have been loosened, the sand is removed, and the filter is filled with a new filter medium.

In this post, you will find detailed instructions on how professionals change the sand filter system’s sand. In addition, with the tips, you will learn what to look out for to avoid consequential damage to the system and problems with water treatment.

Which sand is right for the sand filter system?

Perhaps this is your first sand change in your pool filter, and you are wondering which sand should be best used for the sand filter system.

Not all sand is the same, and with the filter system, you can choose between different filter media.

The following types of sand are currently available to private pool owners:

  • Standard filter sand: Filtration with Silex sand.
  • Filter glass: Fine glass particles that are considered to be environmentally friendly.
  • Activated carbon and sand: A combination of activated carbon and sand in multi-layer filter systems.
  • Fibalon: Modern filter medium that serves as a replacement for filter sand and filter glass.
  • Diatomaceous Earth Filter: Filtration with DE earth (organic material).

The following always applies when changing the filter sand in a pool: Always observe the manufacturer’s information on the type of sand with which the filter system should be filled.

If there is no information on the filter medium and grain size, the sand filter is filled with silex sand (grain size 0.4 – 0.8 mm).

In my blog article, the individual filter media and the differences are described in more detail. Just follow the link if you need more information.

When can a sand change in your filter be necessary?

You now know the different types of sand – with which you can fill a sand filter system – and we are getting closer to the actual instructions for changing sand.

Before doing this, you should check whether you have to change the sand in your pool filter system.

New filter sand is always associated with clear pool water, but the sand does not always have to be replaced 1:1. Backwashing is often enough to ensure clean water.

But you can quickly determine whether you have to change the sand in the pool filter.

If one of the following malfunctions occurs, the filter sand should be changed:

  • The filter sand is more than one year old and has been worn out due to heavy loads.
  • You use a flocculant, and the water balance is right, but the pool water remains cloudy.
  • Despite correct use of the flocculant, flakes will form on the pool floor.
  • The pool turns green more often and is polluted with algae.
  • You had black algae (blue-green algae) in the tank, which have also nested in the filter sand.
  • The chlorine consumption has increased dramatically, although the cyanuric acid and all other parameters are correct when testing your pool water.
  • Calcareous water has caused the filter sand to become calcified and weakens the return flow.
  • It comes to cloudiness when vacuuming with the pool vacuum, and the pool is not clean.

Troubleshooting before changing sand is helpful, but the causes are often complex for beginners to identify.

If in doubt, you should change the sand in your sand filter system because – as already mentioned – this is never a loss and leads to clean pool water.

You can read exactly how this works in the following instructions for changing the pool filter sand.

How to change sand in a pool filter

Changing the sand in a sand filter system is not difficult.

The following equipment is required for changing the sand in a pool filter:

  • Garden glove: This is used to remove the sand.
  • Bucket: A simple bucket for the sand is sufficient.
  • Open-end wrench: This is required to loosen the screw connection of the cover.
  • Oil filter wrench: capturing the outer diffuser connector.
  • Slotted screwdriver: Can be handy to spread.

You will indeed have most of the equipment at home in the garden shed. If not, you can find the right equipment in the online shop under the links.

Follow the steps below to change the filter sand, and you’ll be through it quickly. After the process, the sand filter system should run smoothly again and filter your pool water.

The pool water becomes more brilliant, and the usage of a flocculant is reduced.

1. Push out the fuses

When exchanging sand, the first thing to do is push out the fuse for the entire pool area.

This is for your safety and prevents the pool pump from starting unintentionally.

2. Close the pool valves

After the fuse of the pool system is out, all valves of the system must be closed.

This is to prevent the water from escaping after opening the sand filter.

3. Remove the cover and diffuser of the sand filter

The cover of the sand filter system can then be opened to gain access to the interior of the housing.

Now the diffuser (distributor) can also be easily removed.

Keep the gasket, lid, and diffuser in a safe place so you don’t accidentally step on them.

4. Open the water drain

You will find a water drain at the lower end of the filter system. Open the drain and empty the water.

When the water is nearly drained, you can move on to the next step.

Tip: If you loosen the inlet and outlet of the multivalve and use a screwdriver between them to spread, the water will drain away faster.

5. Turn the diffuser connector aside

After the screw connection to the multivalve has been loosened, take an oil filter wrench and turn the diffuser connector to the left.

The connector is simultaneously gently pushed in the same direction with your free hand.

Tip: The screw connections are then closed again to avoid contamination of the thread with sand.

6. Remove the sand from the filter

You can remove the old sand in the next step, but first, you should cover the nozzle with a simple plastic bag.

Rubber bands are tightened around it so that the bag does not fall when the sand is removed.

You can then empty the entire sand from the filter with the garden gloves and put it directly in the bucket for better transport.

Tip: Some advisors recommend removing sand with a wet vacuum cleaner, but this does not have to be bought separately. You can also use an average gardening glove.

7. Close screw connections

Almost there.

After the filter sand has been removed, the drain screw on the sand filter system must be closed again.

Rinse off any sand deposits from all other previously opened screw connections and close them before you move on to the next step.

8. Fill the sand filter system with the new sand

Before you fill the sand filter system with the new filter sand, it is advisable to pour a liter of water into the filter beforehand.

This results in better distribution and trapping of the absorber arms.

Now you can swap the sand.

To do this, the new sand is poured into the system and smoothed out.

When filling, pay attention to the specified filling quantity of the manufacturer and the grain size – you can find more information below in the text.

Tip: If no fill level is specified, the sand is filled up to below the upper nozzle. The grain size should be between 0.4 and 0.8 mm.

9. Concluding work

Filling with the new filter medium is now complete, and the diffuser connector can be turned back to its starting position.

The bag is then removed and the diffuser attached.

Finally, only the cover seal, the normal seal, the cover, and all other screw connections must be carefully rinsed off. Then the seal is put in place, and the sand filter system is closed with the lid.

Tip: Avoid pulling too hard when closing the screw connection to avoid tension and leakage.

10. Backwash your sand filter

Open all valves and backwash the sand filter system – you can read exactly how this works under the link in my blog article.

During the flush, check that everything is tight. If necessary, the screw connections are tightened a little.

Backwashing was only successful when the water in the multivalve’s sight glass was clear. Don’t forget to rinse again afterward.

You can return to regular operation by setting the multivalve to the filter position.

That’s it. You have successfully changed the sand in a pool filter system.

Tip: If the filter cover no longer seals, the cover is bent, or the seal on the sand filter system has to be replaced. Before doing this, you can try to turn the seal.

How much sand goes into a sand filter system?

The amount of sand plays a significant role in the subsequent water treatment.

But how much sand do you have to pour into the sand filter system so that everything works smoothly?

The exact fill level of the sand is usually printed on the housing of the sand filter.

First of all, check whether the manufacturer’s instructions for the amount of sand are available and adhere to them.

If there is no information on the amount of sand, then the fill level should be directly below the upper inlet nozzle of the sand filter system.

In the following illustration, you can see the inside of a sand filter system and where the sand boundary can be.

Pool Sand Filter

An incorrect amount of sand can cause PVC pipes to break and affect filter performance.

In addition to the quantities, make sure to also pay attention to the grain size specified by the manufacturer. If no grain size is given, Silex sand with a 0.4 to 0.8 mm grain size is used.

The next chapter tells you how often you should change the sand in your sand filter.

How often to change the sand in the sand filter?

Manufacturers usually ask for an annual change of the sand in your pool filter, but in practice, it is sufficient to change the sand in the sand filter system every 1 to 3 years.

But why does the sand in the sand filter system have to be changed so often?

The filter sand wears out over time, reducing the filter performance. Furthermore, contamination of the filter sand cannot be ruled out.

Therefore the sand has to be renewed at certain time intervals.

How often the sand has to be replaced depends on how stressed the filter medium was.

If the filter sand is heavily worn, the grains are round and can hardly filter the dirt out of your pool water – an earlier sand change is necessary here.

An empirical value for changing sand in the outdoor pool is every 2 to 4 years (depending on the load). This value can differ in an indoor swimming pool.

It is not a question of an exact point in time and how often the sand has to be changed in the sand filter system.

Ultimately, it would help if you watched for disturbances and symptoms such as cloudy pool water, which can be fixed with a sand swap.

Tip: If the pool water does not get clean during water treatment, backwashing the sand filter system can help. You can find detailed instructions on doing this in the blog under the link.

Questions and answers about changing sand in the pool

Below, you will find further questions and appropriate answers about changing the pool filter’s sand.

I hope that this will remove any remaining questions and provide more clarification.

What grain size should the filter sand have?

To achieve an optimal filter performance, it is advisable to follow the manufacturer’s information on the grain size.

The correct grain size for the filter sand can usually be found on the label or in the user manual of the sand filter system. If no information can be found, Silex sand with a grain size of 0.4 – 0.8 mm is usually used.

The following applies: The finer the sand, the better the filtering out of turbid matter – but the filter sand must not be too fine either.

The whole thing only becomes problematic when you forget to perform regularly a backwash.

Do you have to refill the sand filter system with sand?

The sand filter system filters your pool water best if the fill level is respected.

Backwashing may result in a slight loss of sand, and the sand may have to be refilled.

This happens far more often when using DE soil (10 – 90% sand loss) or with a multi-layer filter system filled with activated carbon.

What should I do if sand ends up in the pool after changing sand?

If sand comes out of the sand filter during backwashing, it is very likely that a pipe is loose or, in the worst case, broken.

This often happens when the fill level has been surpassed or when a lot of force has been used when changing sand.

To solve the problem, the broken part must be found and replaced. You can read more about the problem with the sand in your pool on my blog.

Do you have any further questions about changing sand in the sand filter system?

If something is unclear to you, feel free to contact me at @contactswimfool on Twitter.

Have fun changing the pool filter sand!

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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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