What is your in tank TDS reading?

[Maxx]

Ahh....my goof Boomer. I know there is a difference between RO and RO/DI, but tend to use the two terms interchangably.

Nick

 

[Debnhev]

Hi all,

What is the ideal TDS reading for RO water??

Debbie

 

[Debnhev]

Dohh...i didnt see the previous reply lol lol.Time to visit the opticians lol

Cheers

Debbie

 

[UnresistibleBlu]

"That is RO/DI at 0 ppm not RO. RO will never get that low. RO will be a few ppm. A good guees is +95 % of the tap TDS."

I think what Boomer meant to say is 2% to 10% of tap water readings, rather than 95% of tap water readings.

 

[Barnacle Dave]

I must have got my typhoon membrane from Walter before he switched over?
Tap water is 256 TDS range and after the membrane and DI it is zero.
I have the 100 GPD membrane and it is still going strong for over 3 years now.I have 2 TDS meters and both read the same. ZERO.

 

[UnresistibleBlu]

I must have got my typhoon membrane from Walter before he switched over?
Tap water is 256 TDS range and after the membrane and DI it is zero.
I have the 100 GPD membrane and it is still going strong for over 3 years now.I have 2 TDS meters and both read the same. ZERO.

Dave - have you been monitoring the tds reading after the membrane but BEFORE the DI? That reading will help you understand how well your membrane is working.

 

[Barnacle Dave]

Dave - have you been monitoring the tds reading after the membrane but BEFORE the DI? That reading will help you understand how well your membrane is working.

So long as my out put is zero I really don't care what the ro reading is.
If the filters and di was just changed not long ago and I was getting a reading on the TDS then I would know the membrane would be needing replaced.
But in 3 years I have never had an issue and change filters out along with di when I have a 1 to 2 on the TDS meter/meters.

 

[UnresistibleBlu]

Dave - that's one way of looking at it. However, if your membrane performance was starting to go bad, and its rejection rate was starting to go down, it would pass more TDS to the resin. If the resin has adequate capacity, you'd continue to get 0 tds out of the DI, but over time you may or may notice that the life span of your resin is decreasing. New resin will produce 0 or 1 ppm tds, but the DI life span will decrease.

Blue

 

[Barnacle Dave]

Dave - that's one way of looking at it. However, if your membrane performance was starting to go bad, and its rejection rate was starting to go down, it would pass more TDS to the resin. If the resin has adequate capacity, you'd continue to get 0 tds out of the DI, but over time you may or may notice that the life span of your resin is decreasing. New resin will produce 0 or 1 ppm tds, but the DI life span will decrease.

Blue

That is exactly what I said. If I see the DI needing changed sooner then normal then I will know so there is no reason to check the out put of the RO when you keep a close eye on the out put of the DI.