# Forum Home Renovation Pools, Spa & Water Features  Backwash without rinse

## DBR

Hi, 
My wife and I have owned a salt chlorine pool with sand filter for two years...  when we first purchased the house I had a pool guy visit to provide advice in maintenance etc.  
He explained the importance of a backwash whereby water moves out of the pool and filter..  I was under the impression that the water leaving would be dirty.... he didn't say anything about a rinse after bsckflush..  
But... today I was at a pool shop and the lady said u should always rinse after backwash. Is this always necessary or just better to do?  
Does this mean that for the last two years my backflushing efforts have achieved nothing at all and our pool has unknowingly been full of bacteria etc?     
In terms of flow rate, the flow has been ok as the creepy crawly has been operating fine and I've always ran the pump 10 hours a day.. 
I have read some articles stating that a dirty filter filters finer particles but it's the flow rate that's the problem.

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## mudbrick

The rinse should be done to finish the job nicely. Backwashing flushes most of the rubbish down the drain so you have done the right thing there. Then you rinse to help settle the sand and flush the last bit of crud and dust down the drain not back into your pool.
if you don't rinse you will see cloudy water coming out of the jets for the first 30 seconds or so when u turn the filter back on.

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## Bros

> Does this mean that for the last two years my backflushing efforts have achieved nothing at all and our pool has unknowingly been full of bacteria etc?

  Sand filters won't remove bacteria just particulate matter. The bacteria is removed by the chlorine.

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## DBR

> The rinse should be done to finish the job nicely. Backwashing flushes most of the rubbish down the drain so you have done the right thing there. Then you rinse to help settle the sand and flush the last bit of crud and dust down the drain not back into your pool.
> if you don't rinse you will see cloudy water coming out of the jets for the first 30 seconds or so when u turn the filter back on.

  Thanks mate. Yes I looked into it today and correct me if im wrong but not completing a rinse isn't the end of the world (nonetheless i will from here on) and still cleans out the sand filter.  
In the past I run the backwash for about 5 minutes so I figure that by the time five minutes is up 95% of what was going to come out of the sand filter has already occurred.. today I did a rinse after a 5 min backflush and the water coming out at the start of the rinse was crystal clear which I guess confirms my point..  
Also whilst most web instructions say you must rinse, some others say "consider rinsing" indicating it's not the worst thing not too as any small amount of particles will filter back through the system.  
I guess why I had concern is because of two things-
A) the pool shop lady said my backwashes have achieved nothing because I have never rinsed... (since found out she was wrong)... 
B) with that advice we do get a lot of black spot on our pebblecrete pool surfaces which I'm always scrubbing and battling with..  last Time we were swimming I did a 5 min backflush  without rinse and my three year old got an ear infection...  I blamed myself for this but it's clear and unlikely this was due to not rinsing a backflush while swimming.. rather due to low chlorine or ph..  
Do you think I'm in the right train of thought now?

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## DBR

Thanks bros, yes from my short research today I figure that backflushing without rinsing still cleans the filter out well... it's just a good way to finish the job by completing a rinse to ensure any residue left at the top of the sand filter doesn't return to the pool..     
The lady at the pool shop today made it out like I'd achieved nothing (exact words) by not rinsing but I walked out of the shop thinking she was wrong but then questioning myself... 
I checked with another pool shop today and the bloke said no issue with pool water quality from not rinsing and not the cause for the black spot or my daughters ear infection-  rather this is s chemistry issue ie chlorine ph etc. - so I need to keep a close eye on this and for good measure I'll rinse after backwash..  
Thanks

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## DBR

> Sand filters won't remove bacteria just particulate matter. The bacteria is removed by the chlorine.

  Thanks bros, yes from my short research today I figure that backflushing without rinsing still cleans the filter out well... it's just a good way to finish the job by completing a rinse to ensure any residue left at the top of the sand filter doesn't return to the pool..     
The lady at the pool shop today made it out like I'd achieved nothing (exact words) by not rinsing but I walked out of the shop thinking she was wrong but then questioning myself... 
I checked with another pool shop today and the bloke said no issue with pool water quality from not rinsing and not the cause for the black spot or my daughters ear infection-  rather this is s chemistry issue ie chlorine ph etc. - so I need to keep a close eye on this and for good measure I'll rinse after backwash..  
Thanks

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## mudbrick

Yep exactly what you said. The Rinse is the icing on the cake not the be all and end all. Lol at the shop lady who has no idea at all.  
Blackspot is a pest particularly in pebblecrete pools. 
Black spot hates strong acid. When i need to add acid I pour it straight into the area with the worst black spot. It kills it. May not be the best thing long term for your grout but our pool is about 25 years old and no pebbles have fallen off . And remember chlorine does not kill algae when pH rises above about 7.8 so keep pH low by adding your acid regularly.  
Chlorine is much the same. Once in a while give it a shock with 3 or 4 litres of chlorine. Also add this to the areas with the most black spot. Wire brush helps too. Use one of those Copper algae killer additives if you like I've tried them they are quite good for a few months.
My kids have also had ear aches in summer. It happens but if you keep pH down and chlorine up you'll minimise those issues. 
is it a salt water pool?

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## r3nov8or

Fact: that pool shop lady is a bit of a dick. Check everything she says.  
A lot of good talk about acid and chlorine especially for concrete pools and black spot above, but don't ignore your calcium balance as you don't want water starved of calcium dragging it out of your pool surfaces.  
Have you got a vial on your filter? If so use it to gauge how long to backwash; stop when the vial is almost clear. 5 minutes sounds way too long and will be wasting water and your chemicals. It's a bit like home made pop corn; if you wait until the last *pop*, you will burn (waste) some popped corn  :Smilie:

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## mudbrick

Absolutely, the whole water balance sheet must be kept in check.
Swimart is the best place I've found for accurate water testing though their chemicals are a bit $$.

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## Bros

> Thanks bros, yes from my short research today I figure that backflushing without rinsing still cleans the filter out well... it's just a good way to finish the job by completing a rinse to ensure any residue left at the top of the sand filter doesn't return to the pool..     
> The lady at the pool shop today made it out like I'd achieved nothing (exact words) by not rinsing but I walked out of the shop thinking she was wrong but then questioning myself... 
> I checked with another pool shop today and the bloke said no issue with pool water quality from not rinsing and not the cause for the black spot or my daughters ear infection-  rather this is s chemistry issue ie chlorine ph etc. - so I need to keep a close eye on this and for good measure I'll rinse after backwash..  
> Thanks

  
 I'm no pool expert I have just done some repair work on my daughters pool, pump and chlorinator over the years but I do know what all the hardware does.

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## r3nov8or

> ...Swimart ...

  They have the most annoying ads  :Smilie:

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## DBR

> Yep exactly what you said. The Rinse is the icing on the cake not the be all and end all. Lol at the shop lady who has no idea at all.  
> Blackspot is a pest particularly in pebblecrete pools. 
> Black spot hates strong acid. When i need to add acid I pour it straight into the area with the worst black spot. It kills it. May not be the best thing long term for your grout but our pool is about 25 years old and no pebbles have fallen off ��. And remember chlorine does not kill algae when pH rises above about 7.8 so keep pH low by adding your acid regularly.  
> Chlorine is much the same. Once in a while give it a shock with 3 or 4 litres of chlorine. Also add this to the areas with the most black spot. Wire brush helps too. Use one of those Copper algae killer additives if you like I've tried them they are quite good for a few months.
> My kids have also had ear aches in summer. It happens but if you keep pH down and chlorine up you'll minimise those issues. 
> is it a salt water pool?

  Thanks mate, 
Yes, we've had the pool for close to two years. Over the last two years I have been blazay and ph has been high with chlorine low made worse by a pool Leak (lost 1cm a day) meaning weekly top ups with the garden hose.. 
I'm much more educated now about checking acid, chlorine etc and leak is fixed.... 
In the past I didn't worry about the black spot as the different colour pebbles in the surface disguise it...    
pool shop lady said no health harm whatsoever to the kids from black spot but just rather an eye saw.- that's why I didn't stress about it much in the past... 
I have my reservations about this after conducting my own research but I could be wrong...  info on black spot health hazards on the net seems only to apply to ponds, lakes (covered in it on surface etc) etc related to Cyanobacteria producing cyanotoxins. and we don't exactly drink the pool water- had to think I've done the kids harm by not being more proactive about removing it...   they've never had health problems, just an earache which is gone...        I figure if the black algae was dangerous you would t be able to swim in a pool after scrubbing it..    
In the last three days I completed copper and brushing and did my first super chlorination -- it looks like a brand new pool!!! No black spot in sight--- from now I'll just keep chlorine levels high and acid about 7-7.2....

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## mudbrick

Do you have a test kit? Just keep it between the lines but at the strong end if you know what I mean  :Wink:  
7.0 will likely give you sore eyes.
Sounds like your algae must be wondering what's hit it Lol!
last tip is keep the pool clean of leaves. The humble leaf will break down in the water and release organic matter.
The dissolved organic matter is the favourite food of your old mate Mr Blackspot and other algaes so is the last thing you want in the water!!

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