[Ian101]

Hi ... how do u know when the 4040 membrane needs replacing.

My TDS used to be as low as 6 or 7 but lately nearer 12/14

Does that mean the membrane on its way out ?

Still a newbie some days 

[andyM]

Do the pre-filters need changing?

[Ian101]

Do the pre-filters need changing?

its about a year old so prob yes but not sure ??

how often they supposed to be changed ?

newbie time again

[andyM]

I change mine every 6 months

[Paul Coleman]

Hi ... how do u know when the 4040 membrane needs replacing.

My TDS used to be as low as 6 or 7 but lately nearer 12/14

Does that mean the membrane on its way out ?

Still a newbie some days 

12/14 is fine - depending on circumstances.  If it needs replacing, you'll know it soon enough because production will plummet and TDS will climb rapidly..  Mine is about 015 at the moment.  The best it ever gave was about 008.  The pressure has dropped a bit so that may account for it.  I would let a membrane go to 040ish before discarding it - maybe even a bit more provided that production were sufficient.  Obviously the resin would start to cost though.  It's a balancing act deciding when to discard and it varies depending on circumstances (e.g. is water metered?, how much is the membrane?, how much is the resin?, how's the cashflow? etc.)

[Paul Coleman]

Do the pre-filters need changing?

its about a year old so prob yes but not sure ??

how often they supposed to be changed ?

newbie time again

Change the pre-filters now or you may wreck the membrane completely.  You're lucky to have got away with it for so long IMO.

[christopher b]

wow a year on pre filters, they will have things growing in them let alone weighing a ton with all the muck.
saying that I saw a resin vessel being opened it belonged to a national, when it was opened the resin was actualy green.... honest.......
no wonder they charge so so little!

[David Kent @ KentKleen]

I could really open your eyes on this matter but the forum sponsors would get me banned!

[luther1]

Changing pre filters won't reduce your tds,it will only prolong the life of your membrane

[Lee GLS]

if the prefilters are clogged, won that reduce the water pressure to the RO, which in turn will cause it not to work as efficiently thus raising the TDS?

[luther1]

No 

[Lee GLS]

No 

fair enough. 

[luther1]

I see your point though Lee, but clogged filters won't drastically reduce the bar/psi enough to make the ro run inefficiently. Having said that,i will try it on mine because my pre filters have been in for two years!

[mikecam]

Hi ... how do u know when the 4040 membrane needs replacing.

My TDS used to be as low as 6 or 7 but lately nearer 12/14

Does that mean the membrane on its way out ?

Still a newbie some days 

You should also be taking note of your TDS going into your membrane, that may also have changed. That may answer your own question .  As others have said you should change your pre filters, once your carbon block stops working then chlorine goes onto your membranes and that kills 'em !!

[colinyates]

Just had two cleaned and they are like new again.  Not sure if this service exsists in the UK.  Im in SA so a bit far to post them .
By the way saved myself 60% compared to new.

[Spruce]

Just had two cleaned and they are like new again.  Not sure if this service exsists in the UK.  Im in SA so a bit far to post them .
By the way saved myself 60% compared to new.

Those South Africans.
My nephew had his alternator stator coils rewired on his car not so long back. We won't be able to find someone here who could take it apart to identify the fault - cheaper to put a new one on first time.
I wonder how they clean an RO membrane.
As an experiement, I tried to pump pure water back through it to clean it, but it was knackered afterward.
Spruce

[colinyates]

Hi Spruce

Got a water treatment guy to do it, apparently he uses acid and other chemicals
What a good find he was.

[Spruce]

Those okes out there never ceased to amaze me.

When I ran the after sales service for Bosch Power Tools SA in Johannesburg nearly 20 years ago, the country was number 98 in the world's population ranking and the purchase of Power Tools from our parent company per head was the same.
However, we (Bosch SA) was the largest purchaser of spare parts in the world. The second largest parts purchasers then were the USA and we ordered twice the amount they did.

It used to annoy our Managing Director that the German HQ would pay more attention to me than him from the sales side.

They will always give precedence to repairing something before replacing it. The throw away concept was never understood by the majority of South Africans. It's foreign to most of them. If it's broken - fix it - simples

Spruce

[mikecam]

Just had two cleaned and they are like new again.  Not sure if this service exsists in the UK.  Im in SA so a bit far to post them .
By the way saved myself 60% compared to new.

How does this work then? A membrane degrades with age, it can also foul in the meantime. Regular flushing eliminates the fouling scenario. What 'cleaning' regime makes your RO's like new?

[luther1]

NLR 404 membrane cleaner. Have a google Mike