- What is a sand filter system?
- Cleaning the sand filter system
- Backwash pool - instructions
- frequently asked Questions

The sand filter system is very popular with swimming pools and has a simple function. However, it needs regular maintenance. Our guide to backwashing your pool will show you how.
In a nutshell
- a sand filter system is cheap to buy
- offers efficient filter performance
- regular cleaning required
- the right pressure is crucial
- Backwashing is also necessary with cloudy or milky water
What is a sand filter system?
A sand filter system is a pump that draws water from the pool. This is passed through filter media made of sand. Dirt and foreign bodies get stuck in the filter. The cleaned water is then returned to the pool.
Advantages of sand filter systems
- easy use
- no chemical agents necessary
- inexpensive to purchase
- simple maintenance
- environmentally friendly
However, this only applies if you backwash the pool at regular intervals. Because over time, the filter medium becomes clogged with foreign matter, so that the pressure in the filter increases and no longer enough water can get through the sand.

Cleaning the sand filter system
When it is necessary to clean the pool filter differs from device to device. The following criteria are decisive:
- difference in pressure values
- Suction and delivery pump pressure
- lack of suction of the water
- turbidity of the water
- increasingly low output
If, despite covering, manual cleaning and filtration, a film forms on the water surface or it appears milky, you should also check the sand filter system. It may then be advisable to clean the filter medium.
Notice: If the problem isn't in the sand, you need to check the plumbing as well. This is because dirt can accumulate here, too, leading to blockages.
Backwash pool - instructions
These tips will help you carry out a comprehensive cleaning step by step:
- Disconnect from power: Before you make changes and make the necessary adjustments, the device not only has to be switched off. Instead, the filter should no longer have any power supply. Otherwise, dangerous conditions and injuries as well as damage to the equipment may result.
- Adjust valve: So that the sand filter system no longer filters the water out of the pool, but backwashing is necessary, a conversion is necessary. It is usually sufficient to flip a switch. The operating instructions provide information. Usually the labels "Backwash" or "Backwash" are visibly attached.
- Connect hose: A garden hose must be connected so that the dirty water is not flushed back into the pool and a sensible cleaning can take place.
- Open valve: The process takes place by opening a valve. Depending on how much water has to drain off and whether it has been treated with chemicals beforehand, it may need to be collected or drained off in a targeted manner. Of course, the proximity to the sewage also plays a role.
- Turn on: Once you have made the above preparations to enable the pool to be backwashed, you can reconnect to power. The water must run through until it is no longer cloudy. Depending on the capacity of the pool, this can take a few minutes or much longer.
- Change flushing direction: After these preparations, the valve must be switched back to normal filter operation.
- Subsequent rinsing: Even if the water appears clear, dirt and foreign bodies can still escape when you change the flushing direction again. For this reason, it is important to derive the first liters. Filter operation can only be resumed when the water emerges without contamination.
- Conversion and filtering: If the result is not as desired, lines and all other parts of the filter system should also be checked.

Notice: It is essential to pay attention to the information provided by the manufacturer. Because the different models of a sand filter system can have different requirements. If cleaning takes an unusually long time, you should also consider replacing the filter medium.
frequently asked Questions
How large should the pressure difference be for cleaning?Cleaning is recommended when the difference between suction pressure and water discharge is 5 PSI or more. At higher values, there is not only a risk of clogging of the filter medium. The hoses can also become clogged.
Why is slight contamination beneficial?Because the sand gets clogged with foreign bodies. Like a sieve that gets narrower, the passage gets smaller and the pressure increases. This increases the cleaning performance. However, this only applies up to the point where the filter medium becomes clogged.
How often is cleaning by a sand filter system necessary?There is no general answer to this. A covered pool will rarely need this measure if it is not used very often. On the other hand, a frequently used pool can quickly need a backwash due to hair, dander, sunscreen and dirt.