[Jim Waugh(Albright & Shiny)]

This defies logic

My RO kicks out water at 17ppm  running at a steady (80psi)
It then goes into DI vessel A and comes out at 2ppm
Then into vessel B and comes out at 1ppm.

so you would think that the resin in Vessel B is depleted ! 

Well
Swap A and B around (resin in B is only a month old )

Then it goes into B at 17ppm and comes out at 1ppm.  which it shouldn't do if its depleted???
and when it comes out of A its still at 1ppm...

any ideas ?  could this be too high a flow through the DI vessels? which both hold a full bag of resin in each..  (I'm producing about 120L/hr)

or do I need to pack more resin into them ? they are 24L vessels with a single bag of resin in them?

opinions and suggestions please

[Dave Willis]

Check with another tds meter? Difference between 1ppm and 2ppm is minute - could even be dirty container you are measuring with.

Strewth! that's a massive amount of resin    Tulsion resin by any chance?

[Jim Waugh(Albright & Shiny)]

Check with another tds meter? Difference between 1ppm and 2ppm is minute - could even be dirty container you are measuring with.

Strewth! that's a massive amount of resin    Tulsion resin by any chance?

It is indeed Tulsion Dave..
I know 1ppm  minimal and not a big issue but its the Why that interests me more than anything..
The TDS is all inline 1 coming out of RO one coming out of vessel A and one coming out of vessel B.  When I swap the probes round they replicate the original results so they are all working fine..
Just been reading some old posts and Backflushing has been mentioned so Im going to give that a try..

[Jim Waugh(Albright & Shiny)]

Right this is driving me mad.. I have tried all sorts of combinations of vessels, pressures , flow rates and still the result is the same..

17 going into the 1st DI 2 coming out and into the 2nd DI and it comes out the second one at 2..
swap em and its still 17 going into B comes out at 2 goes into A and comes out of A at 2 !!!!

Do them as single vessels and its the same goes in at 17 out at 2..

You would think that going into a vessel at 2 while  capable of stripping 15ppm off it should come out at 0.. but it doesn't..

Does this mean that as they deplete they simply become incapable of handling anything below their depleted value.. ? in this case 2

Any of you guys that like the science bit out there than can confirm my thinking?
Alex Gardner have you any thoughts on this one?

[Jim Waugh(Albright & Shiny)]

Just had a thought , could I be in need of changing my Charcoal filter? could this be chlorine?

[Dave Willis]

Is the resin in both vessels exactly the same age from the same batch? Were they both filled the same time? Does sound a bit odd. The resin should polish it to zero from 17 as that's not particularly high at all. I know cleaners who clean above this too 

[Jim Waugh(Albright & Shiny)]

Thats the Mystery Dave.
Vessel A is Tulsion from Gardners about 9 months to a year ago.  and to be honest Having it polish down to 2 is acceptable
Vessel B Is Tulsion from Gardners and is a couple of months old !  it started at 0 and has climbed to 2

Im going to change my Carbon block and see what happens over a month or so.

Im Ok with cleaning at 2ppm for a bit