rodi question

mfinn

Premium Member
My rodi unit has been consistently running the same for many years.
Once I switch out the 2 carbon filters and 1 sediment filter the tds going into the di container has been 1 or 2. Usually 1.
Today even after changing the filters the tds was 14-15. So I figured the ro membrane was tired so I put in a new one I've had on the shelf. ( about a year).
Even after changing the membrane out the tds is still 4-5.
Is there a break-in period for a ro membrane?

The 4-5 tds is after 1-1/2 hours of running.
 
The water supply tds hasn't gone up.
It's still in the 36 to 40 range as it has been for years.
 
RO membranes can and will dry out and become ineffective Also let me ask a few questions.

When you changed out your carbon filters did you flush them out before you hooked them up to your ro membrane? If not fine particles from manufacturing can ruin your membrane. Second when installing a new membrane one should run at least 30 to 40 gl before hooking it up to the di resin to get rid of all kinds of crap used in manufacturing of the membrane.

HTH
 
RO membranes can and will dry out and become ineffective Also let me ask a few questions.

When you changed out your carbon filters did you flush them out before you hooked them up to your ro membrane? If not fine particles from manufacturing can ruin your membrane. Second when installing a new membrane one should run at least 30 to 40 gl before hooking it up to the di resin to get rid of all kinds of crap used in manufacturing of the membrane.

HTH

The ro membrane was bought from BRS 12 months ago.
I never have flushed the carbon filters before. I've switched them out many times since I bought this unit 8 years ago.
I don't remember seeing or hearing this from any of the BRS videos or from anyone else.

I did look today at the video about changing out the ro membrane and it does say to run the first 1 hour to 1-1/2 hours down the drain.
 
I admit I have a different brand and in my instructions it says to flush our the carbon filters first. I could be wrong but when making carbon filters do you think they wash all the dust out of them first. Like I said a completely different manufacture of equipment. Just suggestions
 
Your DI is just likely exhausted..
Its the last gate.. If any TDS is coming out the last gate and you didn't change the DI then it seems the DI is just exhausted..
An RO membrane should last for 3-5 years normally..
 
Your DI is just likely exhausted..
Its the last gate.. If any TDS is coming out the last gate and you didn't change the DI then it seems the DI is just exhausted..
An RO membrane should last for 3-5 years normally..


I have a dual tds meter and 1 is before the di and 1 is after the di.
That's why I said the tds going into the di is now in the 4-5 range after changing the ro membrane.
 
I admit I have a different brand and in my instructions it says to flush our the carbon filters first. I could be wrong but when making carbon filters do you think they wash all the dust out of them first. Like I said a completely different manufacture of equipment. Just suggestions


I will be doing this from now on.
It certainly makes sense.
Thanks
 
It sounds like your RO membrane is bad. You should be seeing at the minimum a 95% rejection rate and more likely 98%. Your current rate is 90%. I would take the RO membrane out and reseat it just to make sure that isn't the issue. It that doesn't help then let it run another hour or so and check. Do you have a handheld tds meter. If so check your water with it to make sure the inline is working correctly. Also, if you haven't done it lately, change the battery in the inline just to make sure that isn't the issue. I've heard old batteries can cause false readings.

FYI, changing the carbon and sediment filters has no effect on tds.
 
yep rinse carbon for a few minutes.

like you I check ingoing to DI and outgoing TDS

Like you I have clean water to start with, you should have 0 -1 coming out the RO before DI like you usually do.

I'm with opus, the membrane is toast
 
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