How Does a Pool Sand Filter Work? The Simple Secret to Clean, Clear Water.
A clean, clear pool is the result of a highly efficient, unseen process that happens behind the scenes in your plant room.
For commercial aquatic facilities, this process is largely managed by one of the most reliable pieces of equipment in the industry: the sand filter.
At Trisley’s Hydraulic Services (THS), we not only build and maintain state-of-the-art filtration plant rooms, but we also believe that understanding the basics of this equipment is crucial for every facility operator.
So, how does this simple, robust piece of technology ensure your water is always ready for patrons?
The Mechanics of Filtration: A Three-Step Process
A sand filter is essentially a large, pressure-rated container filled with specialised filter media (often sand, glass, or zeolite). The mechanism relies on depth filtration—meaning debris is trapped throughout the entire bed of sand, not just on the surface.
Here is the simple process that keeps your commercial pool water sparkling:
Water Enters the Filter: Water is drawn from the pool and pushed into the top of the filter tank by the circulation pump.
Debris Gets Trapped: The pool water is forced down through the dense bed of media. As the water passes through the sand, the sharp edges of the particles act as a natural barrier. This process traps debris and particles as small as 20 microns.
Clean Water Returns: Once the water reaches the bottom of the filter, it is collected by lateral pipes and flows back into the pool.
The Key to Efficiency: Backwashing
As the filter runs, the collected debris accumulates and clogs the spaces between the sand particles. This build-up, called "filter cake," eventually restricts the flow of water and raises the pressure inside the filter tank.
Regular backwashing is key to keeping your filter efficient. This simple maintenance procedure reverses the flow of water, flushing the trapped debris and contaminants out of the filter bed and sending them to waste.
Neglecting backwashing can lead to reduced flow rates, increased pump strain, and, ultimately, poor water quality.
Our Preventative Maintenance Agreements (PMAs) ensure these critical checks are never missed, extending the lifespan of your filter media and maintaining peak efficiency.
Reach out to Learn More
At THS, we specialise in filtration repair, replacements, and media changes. If you are experiencing issues with your commercial sand filter or need expert advice on maintenance procedures, contact our knowledgeable team today!