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UK Window Cleaning Forum => Window Cleaning Forum => Topic started by: AJ on July 16, 2009, 08:01:54 pm

Title: rising TDS
Post by: AJ on July 16, 2009, 08:01:54 pm

Changed 40-40 membrane 1 year ago.
Always run at 12 - 18 tds before DI.
Changed pre filters two weeks ago - lovely - TDS 7 before DI.
Just gone out there, TDS 089 before DI.

Baffled ??? ???

Any ideas lads?

Cheers
Alan

Title: Re: rising TDS
Post by: easy on July 16, 2009, 08:05:39 pm

Have you waste water coming out?

You may have a blockage pushing the waste back into your tank giving a high reading.

Tony.

Title: Re: rising TDS
Post by: AJ on July 16, 2009, 08:11:12 pm

Waste is fine. I have had it on flush for 1 hr trying to get the reading down.

Title: Re: rising TDS
Post by: leapstallbuildings on July 17, 2009, 11:02:05 am

Quote from: AJ on July 16, 2009, 08:01:54 pm

Changed 40-40 membrane 1 year ago.
Always run at 12 - 18 tds before DI.
Changed pre filters two weeks ago - lovely - TDS 7 before DI.
Just gone out there, TDS 089 before DI.

Baffled ??? ???

Any ideas lads?

Cheers
Alan

Are you saying you left it nearly one year before changing pre-filters?  If so, that is too long.  It should be at least half yearly and possibly even every 3 - 4 months.  If your sudden rise in TDS has been accompanied by a sharp drop in pure water production, you may have to get new membranes.  That is the worse case scenario.  However, it looks unlikely to be that because the problem has only occurred AFTER the pre-filter change.  This causes me to wonder if the pre-filters are correctly seated within their housings with the rubber rings in place etc.
Another possibility is that there may have been a substantial drop in water pressure for some reason that may not be immediately obvious (the cause need not be immediately local to you).

Title: Re: rising TDS
Post by: AJ on July 17, 2009, 12:10:19 pm

The pre filters are changed every 3 months, the membrane was changed a year ago.
I think your ideas about the pre filters might be something. is there any way to check if Chlorine is getting past the carbon filter?

Cheers
Alan

Title: Re: rising TDS
Post by: leapstallbuildings on July 18, 2009, 09:13:39 am

Quote from: AJ on July 17, 2009, 12:10:19 pm

The pre filters are changed every 3 months, the membrane was changed a year ago.
I think your ideas about the pre filters might be something. is there any way to check if Chlorine is getting past the carbon filter?

Cheers
Alan

Although I've not done this since school, I remember that litmus paper could be used to test liquids for acid or alkali content.  I've not tried it with WFP though.

Not got time to check but maybe there is something here for you?

http://www.google.co.uk/search?hl=en&safe=off&num=100&newwindow=1&q=testing+water+%2Bchlorine&btnG=Search