Do You Need Chemicals With A Sand Filter?

Having a swimming pool at home can be absolutely amazing, especially during those hot summers when all you want is to dip into some water to cool down and chill in the shade with some ice-cold drinks.

However, swimming pools require a lot of maintenance and upkeep, so that they can function properly and so that the water is crystal clear blue and safe to swim in.

One of the most important parts of pool maintenance and upkeep is the filter. Now, there are many different types of filters for pools. One of the most popular and commonly used types of filters is the sand filter.

Do you need chemicals with a sand filter?

But when you’re maintaining a sand filter, do you need any chemicals? How do you keep a sand filter clean and in top shape?

We can answer these questions, and a few more, so that you know all the basics about making sure your sand filter is up to shape and regulation. Let’s get right into it!

What is a sand filter?

Let’s start by clarifying exactly what a sand filter is so that it’s easier to understand how it works, and therefore what it needs in order to be kept in top working shape.

A sand filter is a type of filter that uses sand in order to filtrate the water. The water is made to pass through the filter, which is filled with sand. As the water sinks through the sand, it becomes purified.

This works because the dirt particles get trapped in the fine pores of the sand, so that the water comes through the other end cleaner, and therefore filtered.

This is a filter technology that is used especially for pre-filtration and for disinfection of equipment, and also to prepare liquids for micro and ultrafiltration.

Sand filters are also commonly used in recirculation systems, rinse water processes, irrigation systems, ground water cleaning, and many many more, including swimming pools!

It is important to note that the sand filter does not filter the dissolved salts that are contained in the water. The only thing that a sand filter can filter out of the water is solid particles, such as big dirt particles, organic material, or algae.

Materials that become dissolved within the water, or that are too fine and small, will not be filtered by the sand. This is why sand filters usually come hand in hand with another system, and why they act as the first step in water filtration, and not the only one.

Do you need chemicals with a sand filter?

Now we can get into the main question: do you need chemicals with a sand filter? The answer, as a general rule, is no.

It is true that some people do use certain chemicals to clean out the sand filter every now and then, specifically chemical soaks.

However, this isn’t technically needed (in the majority of cases), as sand filters are very low-maintenance and only need to be cleaned every few months.

Instead, the way in which sand filters are cleaned is by being hosed down and backwashed. That’s it. And then, of course, every few years, the sand will need to be changed as it will eventually stop being effective.

Using chemicals, in fact, can actually cause sand filters to deteriorate a lot faster. Things such as chemical soaks can deep clean the sand filter, yes.

But at the same time, these chemicals are very harsh on the filter, causing it to deteriorate sooner. This means that people that use chemicals with their sand filter end up having to clean the sand filter a lot more often and having to replace the sand a lot sooner than average.

Tips for caring for your sand filter

As we’ve explained, chemicals are not needed with a sand filter. In fact, chemicals can cause your sand filter to require more maintenance than average, as the chemicals cause deterioration at a faster rate.

There are cases in which chemicals can be used in a beneficial way, and are even recommended. But on average, and as a general rule, you should not have to use chemicals with your sand filter.

Instead, here are some tips on how to care for your sand filter, so that it runs smoothly and effectively:


Backwashing is the main maintenance that you will have to perform on your sand filter, and it is something that should be done roughly about once a month. If your pool is used very frequently, then up it to a few times a month, to ensure that the filter is working properly and the water is clean.

When backwashing the filter, you essentially just have to flip the pump off and turn the valve into the backwash setting. Then you flip the pump back on. (If you are unsure of how to do this, check the manual of instructions to figure out how to get onto the backwashing setting in the filter.)

You then let the pump run for a little while, before turning it off and resetting it to the normal setting.

This will clean out the sand from the filter so that it is able to keep on filtering the water.

Changing the sand filter

Every few years, depending on the regularity with which you use the pool, you should change the sand filter. By changing the sand filter, we mean changing the sand within the filter.

So you get new sand and place it in the filter so that it can be effective and clean the water properly. This is because over long periods of time the sand loses its effectiveness.

Don’t clean the filter too often!

Top tip: the sand filter actually works its best when it is a little dirty. So not too dirty that it is no longer efficient, but slightly dirty so that the sand has more grip to it, and therefore catches more dirt.

So basically, you shouldn’t over-clean your filter, because a bit of dirt in it is actually beneficial, and helps it work better!

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