The type of sand for the sand filter system plays a crucial role in the water treatment in your pool. But which filter material is best suited for the sand filter system, which grain size is ideal, and how much sand goes in a pool filter?
In addition to standard filter sand (Silex sand), you can use filter glass, fibalon, DE soil, or a combination of active carbon and sand in the pool sand filter system. Silex sand with a grain size of 0.4 – 0.8 mm and the filter glass works best in pool water treatment.
In this article, I will introduce you to the most common filter materials for the sand filter system in your pool. I’ll make comparisons, explain the advantages and disadvantages.
Which sand is the best for the sand filter system?
Perhaps this is your first sand change, and you are wondering which sand should be best used for your sand filter system.
Not all sand is the same, and in the pool filter system, you can choose between different filter materials.
The following types of filter material 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.
- Active 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).
Remember: Always observe the manufacturer’s instructions with which type of sand your filter system should be filled. If no information can be found, the sand filter is filled with Silex sand (grain size 0.4-0.8 mm).
The individual filter media and the differences are described in more detail in the following subsections.
Standard sand for the pool filter
The standard pool filter sand is silex sand, which is most often used in private pools.
The grain size is approximately 0.4 – 0.8 mm, and you can achieve 15 µ (microns) filtration. The filtration can be increased by using a flocculant.
The sand is inexpensive, lasts a long time in the filter system, and proves to be unproblematic when cleaning through a backwash.
Furthermore, the sand is suitable for using all pool chemicals such as flocculants, algaecides, and disinfectants like chlorine.
As a rule, the filter sand is changed at regular intervals every 1 to 3 years – heavy use can make it necessary to change it earlier.
Filter glass as an effective filter medium in the pool sand filter
The filter glass is considered an environmentally friendly filter medium for water treatment in your pool.
It is made from the excess white and green glass production in the glass industry and is 100% recyclable.
The unique manufacturing technology enables excellent filtration and prevents the filter medium from clumping quickly.
In addition to efficient filtration, the formation of bacteria is also slowed down, as no bacteria collect on the smooth surface of the glass.
Another advantage of the filter glass is that the system does not have to be backwashed often, and you save electricity costs.
The only question that remains to be clarified before buying is which grain size of the filter glass is the right one for your pool filter.
Grain size of 0.3 to 1.00 mm is recommended for filter glass. This grain size enables a filter fineness of 5 µ and is therefore 30% more efficient than conventional sand.
And when do you have to change the filter material in the sand filter system?
The filter glass in the pool filter system is changed every 3 to 4 years, depending on the load.
I need to mention: Most pool shops try to sell filter glass as a future-oriented alternative to conventional filter sand.
But the truth is, if there is a blockage with fine particles, strong oxidizing agents such as active oxygen are necessary to remove the impurities – backwashing is sufficient for sand.
Combine active carbon and sand in the pool sand filter system
In a multi-layer filter system, the sand is combined with active carbon.
This is very practical, as the activated carbon is also excellent at filtering manganese, iron, and other cloudy substances from your pool water.
Even combined chlorine and the by-products of chlorine are filtered out of your pool water with the activated carbon.
The disadvantage, however, is that when the sand filter system is backwashed, the activated carbon is consumed and has to be refilled repeatedly.
With this pool filter material, those who are not afraid of the extra effort will have long-term clean water in the pool.
Fill the Fibalon into the sand filter system
One of the most modern filter materials for the pool is fibalon, made of polymer fibers and silver ions.
With a filter performance of 8 µ, more thorough water treatment is possible than with silex sand.
In addition, the fibalon has a low weight, which makes it easier to change the filter medium.
The fibalon 3D or the fibalon rope is available from pool retailers. The distinction is simple:
- Fibalon 3D is to be seen as the basic product.
- Fibalon Rope consists of a bundled network of filter balls and is easy to use.
In addition to its high dirt absorption capacity and durability, the fibalon is certified according to standard 100 Oeko-Tex.
However, the disadvantage of the fibalon is that the use of liquid flocculant leads to clumping and should therefore not be used.
However, it is still possible to use flock pillows or flock tablets in the skimmer.
DE earth as filter material in swimming pools
The filtration with DE-earth takes place in a DE-filter (Diatomaceous Earth Filter) – this is earth, which consists of microscopic skeletons of organisms. Source.
Filtration down to 5 µ is possible with DE soil. While this is handy for water filtration, using DE soil is inherently tricky.
Backwashing can be problematic as the filter medium often becomes sticky in combination with grease. This means that the filter system has to be opened and cleaned by hand in the worst case.
Furthermore, in practice, a loss of the filter medium is to be expected during backwashing – the manufacturer’s information here fluctuates from 10 to 90%.
The loss of the filter medium in the pool is not unimportant when you consider that lost filter material has to be refilled, which results in extra effort and costs.
Tip: I will explain to you in my blog article how you can easily remove sand from your pool floor and what the causes are. Just follow the link.
Questions and answers about the pool filter sand
In this chapter, I answer questions that readers have sent in.
In this way, I will clarify your questions regarding the pool filter sand.
What is the sand filter system filled with?
Various sand filter systems are available on the pool market.
But you shouldn’t make the mistake of believing that every filter system is filled with normal sand.
Using the wrong filter medium leads to poor filtration performance and can damage your pool system.
That’s why you always have to follow the manufacturer’s instructions. Read the user manual for your system.
However, if you have bought a used sand filter system and no information can be found on the filter, Silex sand is used for filling by default.
Which is better for the pool filter – sand or glass?
Sand is mainly used in private pools and is significantly cheaper than filter glass.
The filter performance of the filter glass is considered more efficient, and the problem of germ formation is reduced.
In practice, however, there are no restrictions on water treatment in swimming pools with conventional filter sand.
Whether you use sand or filter glass is up to your personal preference.
It is important to follow the manufacturer’s instructions and check filter glass compatibility before filling.
How much sand goes in a pool filter?
After I have shown you the best filter materials for the sand filter, it only remains to clarify how much sand has to be filled into the filter system.
Typically, the manufacturer provides information on how much sand is filled into your sand filter system.
You can find this information in the operating manual or marked on the sand filter system.
I cannot mention it enough, but it is important to keep to the fill limit so that the PVC pipes do not break, and consequently, sand is washed into the basin.
If there is no information on the filling quantity of the sand, the sand filter system is filled just above the standpipe. This is roughly 2/3 the height of the sand filter – you can find an illustration in my article on sand swapping.
Do you have any further questions about filter materials for the sand filter system?
Contact me at @contactswimfool on Twitter, Facebook, or YouTube. I am happy to help you personally.
In this sense, have fun changing sand.