# Forum Home Renovation Pools, Spa & Water Features  sand in filter

## gymeamal

Every time I go near a pool shop I am told that one must change the sand in the filter on a regular basis every five of six years, how important is this or is it a plan by the pool shops to get another revenue stream.

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## m6sports

dont replace it  
about 3 years ago my mother started having alot of trouble with algae and asked the pool shop to replace the sand as she had been told its because the sand is old 
( 15 years old )  
he convinced her to not touch the sand but in upgrade the salt water salt water chlorinator in which she did  
and her pool is now crystal clean  
she was told the only time you would need to replace the sand is if oil gets spilt into the pool and clogs up the sand

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## SilentButDeadly

You don't need to change it....but you may need to check every five to six years that there is still enough sand in there to do the job properly.  Regular backwashing tends to eject a small amount of sand each time so it is possible to lower the sand level a bit over time

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## Gaza

the sand is like a vacum filter, if the filter bag fills up with crap the vacum stops sucking,  
if the sand becomes full of rubbish and compacted then the volume of water that can pass through drops and the sucktion  drops off. 
i changed my sand a few years back when the pool went green and there was very little water flow / suction. 
the guy at the pool shop throught i was nuts doing it myself, i just brought a few bags of sand, tipped the filter over bailed the sand out and filled it up. 
away it went better than new, cost about $100 BUCKS and an afternoon.

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## Geoff2005

You should be able to tell how your filter is going by the pressure gauge. In any particular setup with pump/filter and pool cleaner attached or not after a little bit of time you will know what the particular pressure should be and when time to backwash. When you backwash you should watch what the discharge and run backwash till almost clear. 
Had the same sand for 12 years, no problems.

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## scubabob

i worked in the pool industry for quite a few years - and still do ocassioanlly (as a diver primarily, finding and repairing leaks).  The sand is in your filter for a reason.  This being to trap bits of skin, leaf matter, bugs and other fine materials that would otherwise simply circulate around in the water.  Imagine seeing the sand magnified, like scoria.  It has jagged edges and the minute bits of foriegn matter get caught on these edges and is trapped inside the filter.  Over time, the sand particles rubbing against each other wears the edges smooth, thus not allowing it to do its job.  No sharp edges to catch anything on results in nothing getting trapped. 
Also, over time it tends to compact, which in itself will not only increase the filter pressure but prevent the water from being filtered properly.  Backwashing will loosen it up and wash all the bits out to the drain but if its worn out, it's not doing its job. 
It is not a difficult job to replace the sand, a little messy and a few rules to abide by but all in all it's not that hard.  If you do change it, backwash it well straight after so the "sand dust" gets washed out the drain and not into your pool. 
AND the worst thing ever for sand filters is sunscreen.  Serious.  It floats off in the water, goes into the filter and coats the sand particles with a fine coat of oil which lets bits of stuff slide off.  But, better than kids with sunburn. 
Hope this all helps

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