Home RO chemical testing - is there any point ?

[Chris Bates]

I have been looking at our chemical tests for RO water. Particularly with regard to home patients

We have had a few failures for Calcium before we started using softeners.

We have never had any other failures.

Any sample is only ever going to be a snapshot for a few seconds of run time.
Incoming contamination could happen at any time or could have been present for months before we sampled.

The water suppliers test frequently and should inform us of any contamination.

If a membrane is failing then conductivity will rise and alarm limits can be set quite low.

These tests cost thousands of pounds each year and I wonder what use they really are.

Is this just an expensive box ticking exercise with no real world  benefits.

I expect there will be strong views on this - We currently pretty much follow the RA guidelines but haven't taken a Table 2 or 3 sample for a while.

[Ian Wilde]

Hi Chris,

The only failures we have are Aluminium and sometimes Nitrate.

The aluminium we tend to catch as it rises.  Without the sample though we wouldn't catch it at all as there is a negligible effect on conductivity (please feel free to correct me).  I think on average though we only see aluminium rise above the limit about 3 times a year throughout our home program which is 60+.

We have RO units where we have noticed the conductivity rise to say 20uS (incoming 85uS) - have tested the output and it still passes the levels set in the standards.  Due to the rejection ratio falling we have still changed the membrane though - something I am still trying to decide if it the right decision.  Does rejection ratio over-rule sample results as a safety measure???

The nitrate is only in particular locations - usually rural so I presume that it is washing from the land into the water network.

As we found out through the presentation at the 2017 National Conference a lot of these contaminants can take some time to have an effect on the body which is probably why the guidelines say a 6 monthly sample is ok.

I'm sure the chemical testing is <£20 a shot so for peace of mind we personally here will continue to do it.  We tie it in with an RO disinfection anyway (which we do) so the technical time isn't wasted.

[Chris Bates]

Hi,
Interesting. We've never had a failure on NO3 or Al (apart from one Al failure on a new main plant which the test house admitted was an error ).
Also where do you get you chemical testing done for <£20 ? Ours costs >£70 for table 1.
Chris

[Ian Wilde]

Hi Chris,

We are using ALS and purchasing their Mandatory Suite.  This with TVC and Endo is the only tests we run.
I think the Mandatory Suite is around £16.