# Testing an RO unit



## tiptreemick (4 Apr 2017)

Oh knowledgeable people out there. My RO unit is three years old, used regularly, summer and winter, and is still producing water with a TDS reading of 16 as opposed to my tap water having a reading of around 270. The RO output flow seems to be no less than when new. Does this indicate it is still effective and usable or should I replace it ?


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## ian_m (4 Apr 2017)

Try flushing the unit and see if TDS improves.

Test the RO water for chlorine and ammonia as RO units do not guarantee removal of chlorine and chloramine, especially if the state of any pre-filter is unknown.

Life of RO unit and more importantly the pre-filter depends obviously on usage, care of membrane and how much chlorine/chloramine is present in your water.


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## tiptreemick (4 Apr 2017)

Thanks for your reply. I was under the impression that a reduction in TDS values (p.p.m ?, gms per litre ?, carrots per bunch ?) of 270 to 16 was indicative of an effective RO unit, maybe not then.
I can deal with chlorine (no chloramine in local water supply apparently) by other means.


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## dw1305 (4 Apr 2017)

Hi all, 





tiptreemick said:


> I was under the impression that a reduction in TDS values (p.p.m ?, gms per litre ?, carrots per bunch ?) of 270 to16 was indicative of an effective RO unit, maybe not then.


PPM, but really measured as conductivity in microS and converted using ~0.6 as a conversion factor (10 microS = 6ppm TDS).

It is a higher TDS reading than you should get, suggesting that at least one of the components needs replacing. If the carbon filter is allowing chlorine through it will damage the RO membrane.

cheers Darrel


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## tiptreemick (5 Apr 2017)

Thanks for that info Darrel. I'll toddle off down the local dealer and get a new RO unit. I needed a good excuse to go there anyway.

Mick


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