[thompsonr]

Hi all
I have a ro-man 4 stage ro/di unit.
I get the following readings
Tap 380 (hard water area)
After ro 008-012 (95% removal  which is good)
BUt after di it is 004.

I have tried a 50/50 resin mixand also a 60/40 mix (Tulsion)

The di cannister is a litre size one.Should I get an extra di unit added to the unit or is there no point, and accept that a hard water area means higher readings
Anyone in a hard water area who has a similar size unit had this prob?.Thanx!

[Andrew McCann]

I think your TDS meter is reading slightly wrong.

004 is fine to work with but if it bothers you get some calibration solution from RO-MAN and test your meter.

Andrew

[Alex Gardiner]

I think your TDS meter is reading slightly wrong.

004 is fine to work with but if it bothers you get some calibration solution from RO-MAN and test your meter.

Andrew

I agree that it is probably your TDS meter.

Is RO-Man still trading? All the clients I talk to have been unable to get anything from them recently.

[DASERVICES]

I have never used an r/o system but can someone tell me the set up of the di vessel. For resin to work the flow of the water needs to come from the bottom of the vessel then filter through the vessel to the top. What is the attachment in the vessel to allow this to happen in a r/o system.

I have a funny feeling what is happening here the water is not filtering from the bottom to the top but just going in and out of the top of the vessel which means it will have little effect. Just a thought but could be wrong. Has anyone got a pic of the set up inside the di vessel of a r/o system.

Thanks

Doug

[thompsonr]

Thanks for the replies.Re the tds meter I have 2 and both read the same, but will get the calibration solution as a back up.
The 2 pics show the di cannister in the casing and also the inlet and outlet of the water in the chamber in which the cannister sits.The gasket at the top of the cannister sits tight onto the outlet and so there is no water  passing in and out without passing through the resin.
Regarding the flow I have reduced the rate down to the minimum operating pressure of 40psi and this has no effects.
Shall I accept that 000 is not going to happen?Most advice seems t be that 004 is ok.

[mark dew]

Is 4 the best you can get?
Have you tried testing the tds of the water in your van tank?
I use the same di vessel as you and the tds after my DI has been high. But  in my van it is lower.

Getting another DI vessel and doubling them up won't be a bad thing either. Your resin will last alot longer. Though i am still using from a sack that is 2 years old. Still getting 1ppm with 1 vessel like yours.
Always got 0ppm when i had 2 in tandem.
I only use 1 now as I can't unscrew the other one to change the resin.

[steve a]

I am no expert but I reckon if you could get hold of a decent size DI vessel11-25litre then this should help in reducing your TDS as the water is in contact with more resin for longer.

Just my opinion.

Steve a

[DASERVICES]

Hi Ray,

Thanks for putting on the photo and I am 99% confident you will not get 000 tds with that di vessel. The resin is working as it is reducing your TDS fractionally but the amount of surface the water is running through is not enough.

If your TDS was around 002/3 after r/o then it would work but your TDS is up to 012 which is too high for such a small volume of resin. The one thing that stands out is the flow from the top of the resin is not evenly distributed through the resin. There is one flow going through the middle so therefore is only channeling through a fraction of the resin instead of all of it.

This I feel is you main problem. To rectify this you will need a larger di vessel.

These are my views which I am certain is the problem as volume vs flow rate and TDS level is a key element in getting 000 TDS.

[steve a]

 
I'm sure I just said that

steve a

[DASERVICES]

Yip, you did but was too lazy to read the message when the warning sign came up someone had posted, sorry should have looked.

[steve a]

's okay

[thompsonr]

Thank you all for the advice.It is a real eye opener!
If I buy an additional Di vessel(11 litre seems to be the best fore me) how can i connect it to my ro/di system.The tube out of the Di chamber is 1/4 "> Is it a matter of getting adapters as all the di vessels I have seen seem to have hozelock fittings or do I have to re jig my whole ro system?

[dmlservices]

make sure you pack resin in tightly,

this happened to me when i first got my ro.

also if ro is not used for a day or 2 ( when holding tank is ful ),

 i will dissconect di feed and run to drain, flush system for a while , put into production mode

, then i reconnect to di when reading has dropped to around 004 ,

continue to run to drain for a few minutes, reconnect to holding tank when tds shows 000.

the above is what i do ,

saves on resin usage as well.

daz

[steve a]

Thank you all for the advice.It is a real eye opener!
If I buy an additional Di vessel(11 litre seems to be the best fore me) how can i connect it to my ro/di system.The tube out of the Di chamber is 1/4 "> Is it a matter of getting adapters as all the di vessels I have seen seem to have hozelock fittings or do I have to re jig my whole ro system?

If buying new then i  think 7you will be able to specify connections or failing that should be able to get the john guest adapters to fit.

one of these may do the trick ht tp://www.uk-plumbing.com/john-guest-speedfit-fittings-john-guest-speedfit-reducers-c-374_389_390_394.html
Steve a