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Problems with TDS levels

Pepsi

Member
Messages
45
Location
Hertfordshire
Hi everyone.  Ive been a WFP for 18 months now.  I have changed the sediment and the carbon and the DI resin like I have done every 3-4 weeks when my TDS meter shows 005 (I dont like to work to 010).  The RO system was changed a few months ago and the water going into the RO is reading approximately 30-33 on the TDS meter.  I live in a very hard water area but I know ideally it should be 25 and under.  After changing all the filters the TDS reading goes down to 000 ppm usually but last week, after changing all the filters, 2 days later the TDS reading was 005 so I changed the DI resin as only a couple of days earlier I changed the pre-filters.  I got it down to 000 again but next day I checked the TDS and it was back up to 004.  Any ideas please?  (PS someone told me that the DI resin sometimes has to settle down but I've never had this problem before).

 
I am bit baffled what exactly is your set up as a tds of 30-33 is a soft water area, Are you running water through the di vessel first then into your ro if so you are doing it the wrong way around. It should be ro first then di. 

 
I agree with the above......

if your tds is hard water, then you'd expect it to be 150ppm plus atleast going into the ro. 

Your set set up should be like this.....

tap water

 (100 ppm for example) 

sediment filter

(no drop in tds)

carbon filter

(no drop in tds) 

Into ro membrame 

(Tds of 002-003ish) 

di vessel 

(000 tds and pure water) 

from what you've explained something seems a miss. 

 
Last edited by a moderator:
Hi.  I live in a hard water area (between 350 and 400).  The water runs through the RO, then through the pre-filters and then lastly through the resin.  Any ideas please?  It has worked like this for 18 months without a problem - its just this last lot of Unger resin - could it be the resin which is at fault?

 
Di resin doesn't need to settle, Detach di and and roll vessel across the lawn to agitate the resin beads as they develop a water channel through resin then check tds again under production it might get you through a few more days. Then buy some different resin once you have used up what you have got. 

 
Hi.  I live in a hard water area (between 350 and 400).  The water runs through the RO, then through the pre-filters and then lastly through the resin.  Any ideas please?  It has worked like this for 18 months without a problem - its just this last lot of Unger resin - could it be the resin which is at fault?






Hi, 

again..... if what your saying is right, then you've got things round the wrong way. 

It should be pre filters first, then ro membrane, then Di resin. 

The pre filters take out the sediment and chlorine from your tap water to protect your ro. If you've got this the wrong way round then your membranes will no doubt need replacing. 

 
Last edited by a moderator:
The correct way is sediment filter then carbon filter then ro filter then resin job done


Sent from my iPhone using Window Cleaning Forums

 
Thank you everyone.  It does run through the pre filters first i.e. the sediment and the carbon, then it runs through the ro and then it runs through the resin.  I have taken what Iron Giant has said and have heard this before i.e. shake it around.  Is it possible I have a dodgy bag of resin?

 
Thank you everyone.  It does run through the pre filters first i.e. the sediment and the carbon, then it runs through the ro and then it runs through the resin.  I have taken what Iron Giant has said and have heard this before i.e. shake it around.  Is it possible I have a dodgy bag of resin?




Glad you've got everything set up right. 

The key key reading you need is what comes out of your ro and before the Di resin. 

Is it reading 30-33 out of your ro? If so your membranes aren't working correctly. You just need to work out why, low water pressure, not seated correctly in the housing etc. 

 
Hi 

yes the reading is 30 - 33 through  R O  what i normally do is put it in a flush for 30 mins to preserve ro then put it on fill after about 10mins get reading from ro water into tank its approx 33 when i know it should be around 25 i only just changed ro about 2 months ago and everything was working ok and have done several filter changes and resin since ro was changed all ok normally change them approx 3-4 weeks as live in v hard water area  thats why i am a little baffled sorry about the pun also just changed resin again and now down to 000ppm which is fine but none to sure how long this will stay as last time a few days later up to 004 sorry to go on its a puzzling one thats why think resin bag ??

 
Hi 

yes the reading is 30 - 33 through  R O  what i normally do is put it in a flush for 30 mins to preserve ro then put it on fill after about 10mins get reading from ro water into tank its approx 33 when i know it should be around 25 i only just changed ro about 2 months ago and everything was working ok and have done several filter changes and resin since ro was changed all ok normally change them approx 3-4 weeks as live in v hard water area  thats why i am a little baffled sorry about the pun also just changed resin again and now down to 000ppm which is fine but none to sure how long this will stay as last time a few days later up to 004 sorry to go on its a puzzling one thats why think resin bag ??




Do You know how much water your going through roughly before the reading rises to 005? 

Also what size is your Di vessel? 

 
I had my tds rapidly rise from ro lately with new membranes

Used to have 75psi from the tap

Borrowed a pressure gauge and checked it and now it is just under 40psi

Recently a neighbour had a water mains burst birst in their driveway which had to be repaired and that coincides with the pressure drop so i reckon they did something then

Also some water companies drop the pressure in summer (something to do with leaks apparently)

You need to check the pressure amd maybe get a booster pump as that is a very high post ro tds

That would make the resin last a lot longer

Also unger resin is pants

Cheaper than tulsion yes but not when you change it more often

I get mine from daqua £75 delivered but lasts a lot longer 

 
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