Your swimming pool is equipped with a sand filter, and you’re starting to think about changing the sand: which type of pool filtration sand to choose?
What is the correct grain size of sand for a swimming pool filter? When should the filter sand be changed? In this article, we’ll help you choose the best sand for your pool filter.
What is Pool Filter Sand?
A pool filter sand is a medium that catches all types of dirt, insects, and debris of the pool in the filter.
The sand filter is the most widespread among private swimming pools, as it is cost-effective and is simple to use.
It comes in the form of a cylinder containing sand, through which the water will constantly pass, depositing dirt, debris, and impurities that have settled in the basin.
The filter captures and retains this dirt, preventing it from returning to the pool for optimal hygiene.
This sand filter is therefore simple to use and effective, provided that the size of the filter is proportionate to that of the pump and provided that the maintenance of the sand filter is regular and rigorous to avoid clogging.
Also, you will regularly have to change the sand in your sand filter regularly, so you need to know which sand to use.
What is the Best Sand to Use in a Sand Filter?
If your pool is equipped with a sand filter, be aware that you cannot use just any sand when it comes time to change it.
First of all, remember to read the manufacturer’s instructions for your filter, because you will find there the recommended grain size and the quantity of sand to add to your filter.
You must of course provide specific sand – a special sand for swimming pools – because this sand has been treated and washed before being sold.
So forget the beach sand. It will only clog your filter. Similarly, construction sand – or sandblaster sand – can be a problem. Of a larger size, it will not have the same efficiency as specific sand. It will indeed let more dirt through.
Sand for swimming pools is mainly composed of silica. This element is particularly recommended for the swimming pool filter since it resists very well to the various chemical products used for water treatment.
The ideal composition of sand in a silica sand filter includes more than 85% silica. Talking about silica sand, you should also know that there are different grades of silica sand.
However, the 20 pool filter sand grade is an effective sand media for the pool filter. They have sand measuring 45 to 55 mm in size.
What Grain Size to Buy?
Swimming pool filtration sand is available in several grain sizes. The finest – particles between 0.4 and 1.3 m in diameter – are ideal for quality filtration. However, as the grains are very fine, they retain dirt better and get dirty more quickly.
Larger grains – between 2 and 5 mm – may be sufficient if your water is slightly dirty. However, this type of sand is used as an underlay to be used in strainers. Larger, this gravel will better complete the filtration.
It will be necessary to use these two types of sand – a fine one at the bottom and a more imposing one above for quality filtration.
Generally, sand with a grain size between 0 and 0.2 is used as an overlay and between 0.2 and 0.5 mm – often called gravel – in the strainers. However, it is possible to find sands with a grain size between 0.4 and 0.8 mm. This type of sand offers a longer lifespan.
Indeed, the larger the grains, the longer they take to wear. Thus, this sand can last up to 3 years.
The uniformity coefficient – or CU – is not to be neglected. For effective filtration, the grains must indeed be of the same size. The filtration will thus be more regular. An effective grain must be hard and not brittle to play its role for many years.
Density also matters. The sand must indeed be heavy and compact enough to filter well. A true density of 2.6 is an excellent choice.
Silica Sand is Indisputably the Best Sand for Your filter
Filtration of your swimming pool is essential to obtain clean water. But for it to be effective, it is useful to choose the right sand. For a flawless result, the type of sand, grade, grain size, and quality are to be taken into account.
In any case, silica sand is the best for the pool. It’s easy to find, inexpensive, and will filter down to 20 microns of sand.