Sand Filter Maintenance

How often should the sand in a swimming pool filter be changed?
As a general rule we recommend changing the sand every five to seven years, while it has been known for filters to go 20 years or more without changing the sand the filter is obviously not as efficient as it should be which means the system costs a lot more to run.

Filter sand is sand that has been specially graded to trap particles in the 20 - 100 micron range and is ground to a size of .45 to .55 mm in diameter and is very rough when new, this roughness makes the sand very efficient at filtering out the particles of dirt in the water, as this roughness is smoothed out the filter's efficiency decreases, which means that the system must be set to run more frequently to accomplish the same task, this in turn will increase the amount of sanitizer used thereby increasing your chemical costs, in addition we find that after five years or so the sand is starting to wear enough to allow dirt to penetrate so deep into the sand that normal backwashing will not clean it completely, the result is shorter filter cycles which requires more frequent backwashing.

One click to open one to close.
As you can see there are many different types of sandfilters but just like a car they most all do the same job.

When do I Backwash my Sand Filter?
When the pressure gauge on your sand filter is reading 8 - 10 lbs above the clean starting pressure (after backwashing) it is time to backwash your sand filter.
This process involves turning a valve so that the water will flow through the filter backwards, flushing out the dirt - Hence the name "back-washing."
Sand filters can have either a push-pull valve (also known as a slide valve) or a multiport valve.
The multiport valve has multi-ports on the valve, usually 6 positions.
Always shut off the filter pump before turning the filter valve.

To backwash a sand filter with a multiport valve
spot  Shut off the pump motor
spot  Press down on valve handle, rotate valve from FILTER to BACKWASH position
spot  Roll out any backwash hose or open any waste line valves
spot  Turn the pump on.
spot  Watch pressure gauge for backpressure and hose for kinks. Be prepared to shut off pump quickly if the     pressure gauge spikes or if the hose kinks up.
spot  Let the pump run for 2 - 3 minutes on BACKWASH or until the water out of the backwash hose runs clear
spot  You can tell if you have not backwashed enough if when you start the pump on FILTER dirt is pumped back     into the pool.
spot  Shut off pump motor and move multiport valve handle to RINSE position & Run on rinse for 15 seconds.
spot  Shut off pump motor and move multiport valve handle to FILTER position
spot  Turn pump back on and note lower pressure. Roll up backwash hose