RO/DI and TDS

[shadofax69]

So I took a reading of my TDS tonight and I got a reading of 8. Now I am assuming this is not bad but I was wondering what part of my RO/DI needs replaced. Is the membrane bad and I need a new one of those or is it the prefilter which is dirty or the carbon. I also have a DI resin that I know needs replaced, but I was wondering which of the major parts is starting to show its age. Just so you know the whole system is only 4 months old.

 

[xtrstangx]

How long was it running? When you start up your RO, you will get a TDS of 40ish and it will slowly work its way to 0 (EVERYTIME you start it up, IME).

 

[fahz]

Your DI resin sounds like it's exhausted and it's a problem because it starts throwing back bad TDS.

Fahz

 

[ohioreef]

My DI resin has never leached back into the water after it was exhausted.

 

[Im14abeer]

4 months? What are your supply TDS? Did you test the product water's TDS when the unit was new? I assume the DI resin was new 4 months ago. If your DI resin exhausted that quickly, you either process a ton of terrible supply water, or something is wrong with your RO membrane. It may not be seated correctly, or have a broken O-ring at the end. Or it could have a tear in it. If you don't find a problem with the membrane, (I don't know how you'd find a tear,) I'd call the manufacturer. That is unless you are the world's best water changer and went through that much water.

 

[ohioreef]

Depends on the DI filter as well, if he has one of the small horizontal units it may very wee be exhausted or possibly channeling.

 

[Paintbug]

sounds to me like the DI resin needs to be changed as well. what reading do you get from your tap water?

 

[shadofax69]

My RO usually runs 0. I have probably made about 1000 - 1500 gallons of water since setting it up. As for the TDS of my tap water I believe it is about 5000 which I know is an extreamly high number but we have very hard water here in Indiana and I have no water softener.

 

[fahz]

5000 or 500?????? With a reading of 500 and a 75 GPD membrane your TDS off the membrane would be 10-15. With a 10 reading two fullsized vertical DI cartridges would have exhausted at about 1000-1200 gallons of production water. Now you didn't tell us what your system consists of so the information I'm giving you doesn't relate to your system. Maybe you should tell us more about your system setup.

Fahz

 

[Im14abeer]

5000, does your water crunch when you drink it?