80+ TDS after membrane. Could use some help.

[Shane B.]

Update on another potential problem. The old restrictor that I removed was listed as 400 ML on the sticker. My new restrictor/bypass I bought is listed at 550 ML. My Spectrapure membrane I just bought is 90 GPD. I think somewhere along the line I got switched around. I'm assuming I should probably get a restrictor that goes with the 90 GPD membrane, or a membrane to go with my 550 ML restrictor. I may also get a new RO housing as mine now has a VERY SMALL drip leak.

 

[COreef8]

Correct - T on the left after the membrane that you can see only goes to a pressure gauge.
Gray T that you asked about = 1st inline TDS meter, coming right out of the supply from my water softener. Usually reads about 430 or so, hasn't changed a lot since i first installed it.
I checked the drain, steady drip. For giggles I checked the TDS and it was almost 500, so it makes sense to me that is the drain line.
I checked the TDS of the water coming right out of the membrane housing before the auto-shut off, any T's, etc. Still at 163.
Could my membrane housing be bad? Is that something that happens? Like drain water leaking into the output chamber?

Man this has got to be frustrating for you! Super weird. With TDS of 500 going into the membrane, it's obviously doing something just nowhere close to the 95%+ rejection you should be getting. As far as forgetting to flush the carbon blocks, I really don't think that would ruin the membrane but I'm not positive.

The membrane housing is pretty simple and unless there is a crack in the plastic, any water bleeding through within the housing would be a result of the O-ring seals on the membrane itself. This would be difficult to check but if you don't find any other possible cause, a replacement housing is less than $10.

If the membrane was installed backwards, it could cause this problem though. The side of the membrane with the 2 small black o-rings was put in first, right?

 

[COreef8]

Update on another potential problem. The old restrictor that I removed was listed as 400 ML on the sticker. My new restrictor/bypass I bought is listed at 550 ML. My Spectrapure membrane I just bought is 90 GPD. I think somewhere along the line I got switched around. I'm assuming I should probably get a restrictor that goes with the 90 GPD membrane, or a membrane to go with my 550 ML restrictor. I may also get a new RO housing as mine now has a VERY SMALL drip leak.

I missed this post. Having the wrong restrictor size can affect TDS but going from 400-550 shouldn't be enough to drop the rejection rate to 66%. I think 500-550 is the correct size for a 90 GPD unit. My unit is 75 GPD and has a 400ml restrictor.

 

[Shane B.]

OK - but what if I accidentally bought a "bigger" membrane? Like - i went from a 50 GPD to a 90 and didn't chagne the restrictor?

 

[KStatefan]

OK - but what if I accidentally bought a "bigger" membrane? Like - i went from a 50 GPD to a 90 and didn't chagne the restrictor?

What ratio do you have now?

 

[Tony Elenbaas]

I had a similar problem, the problem turned out to be a crack between the two end fittings allowing the waste water to flow into the RO outlet. After the housing was replaced it worked properly.

 

[Mjl714]

Ohio, @Buckeye Hydro are your go to experts.

 

[Shane B.]

For those still following, replacing my "new" RO membrane brought my TDS back down to 4 ppm. I changed every single filter media I had in the system, sometimes twice. I have no idea what the issue was, but its fixed now. Assuming i had a fouled/defective RO membrane.

 

[Nick30G]

For those still following, replacing my "new" RO membrane brought my TDS back down to 4 ppm. I changed every single filter media I had in the system, sometimes twice. I have no idea what the issue was, but its fixed now. Assuming i had a fouled/defective RO membrane.

I had a similar issue with high TDS out the membrane and low water production despite more then nominal PSI. I ended up finding it was a bad/fouled membrane as well so I replaced it with a new one.

 

[cromag27 Verified Sponsor]

have you tried checking your tds with a high quality handed meter? inline meters to bad, their batteries go bad and they’re not as accurate as a good handheld. what if all these inconsistent readings are simply from a bad tds meter?

 

[cromag27 Verified Sponsor]

btw, visit the link in my signature for a rodi 101 crash course.

 

[Shane B.]

have you tried checking your tds with a high quality handed meter? inline meters to bad, their batteries go bad and they’re not as accurate as a good handheld. what if all these inconsistent readings are simply from a bad tds meter?

Indeed I did. Both the handheld and inline showed high TDS after the membrane.

 

[cromag27 Verified Sponsor]

Indeed I did. Both the handheld and inline showed high TDS after the membrane.

did you also swap the inline tds meters or replace the batteries? even if the meters were reading incorrect number, it should bounce up and down.

 

[Shane B.]

did you also swap the inline tds meters or replace the batteries? even if the meters were reading incorrect number, it should bounce up and down.

I did replace the inline TDS battery, but i did not replace the inline TDS meter as it was reading within 1-2 TDS of my calibrated hand held TDS meter.

 

[rushbattle]

I think it was seating of the membrane seals in the housing. Sometimes you have to press really hard or add silicone lubricant to the orings.

 

[cromag27 Verified Sponsor]

I did replace the inline TDS battery, but i did not replace the inline TDS meter as it was reading within 1-2 TDS of my calibrated hand held TDS meter.

so the handheld matches both the low and high readings?

the next test i’d do is run it without the membrane and see what the tds readings do. i think you already know your psi is low, but should be unrelated.

 

[Opus]

so the handheld matches both the low and high readings?

the next test i’d do is run it without the membrane and see what the tds readings do. i think you already know your psi is low, but should be unrelated.

His problem is fixed and was either a bad membrane or it was just not seated properly. His psi is 80 so is fine.

 

[cromag27 Verified Sponsor]

His problem is fixed and was either a bad membrane or it was just not seated properly. His psi is 80 so is fine.

no. first post says 46psi and tds post membrane anywhere from 60-250. prior to that it was 4-6. no mention of messing with the membrane in between. so i wouldn’t guess any issues with the membrane not “seated” properly. if anything the membrane could be bad but it must have been crap quality because it doesn’t sound like it was installed for very long and it sure went downhill fast. that’s why there’s spectrapure!!!

 

[Opus]

no. first post says 46psi and tds post membrane anywhere from 60-250. prior to that it was 4-6. no mention of messing with the membrane in between. so i wouldn’t guess any issues with the membrane not “seated” properly. if anything the membrane could be bad but it must have been crap quality because it doesn’t sound like it was installed for very long and it sure went downhill fast. that’s why there’s spectrapure!!!

Then you need to reread his posts. He ordered all new filters including a spectrapure membrane from Premium Aquatics. Post #13 states he got a booster pump and his pressure is 80psi and changed all filters including the ro membrane. He changed out the NEW spectrapure with another membrane in post #28 (doesn't state if it was another spectrapure) and he is now at 4tds.

 

[cromag27 Verified Sponsor]

Then you need to reread his posts. He ordered all new filters including a spectrapure membrane from Premium Aquatics. Post #13 states he got a booster pump and his pressure is 80psi and changed all filters including the ro membrane. He changed out the NEW spectrapure with another membrane in post #28 (doesn't state if it was another spectrapure) and he is now at 4tds.

tl;dr

good to hear.