High TDS readings after ro membrane change

[bioneck47]

I'm getting high TDS readings (around 50)after I changed out my membrane on my 100 gpd ro unit. I tried changing out the housing, tried another membrane, and I'm still getting high tds readings. It also seems like the flow is a little higher than usual. Any help would be greatly appreciated!

[dots]

Did you change the DI resin?

Is this the correct Membrane with the matched restrictor?

Autoflush it for a while, they come with a chemical to inhibit bacterial growth.

[bioneck47]

I'm not sure if the restrictor is the same. I didn't know that you have to change out the restrictor. The new membrane is different though. How do I know which restrictor I need? Also is it normal to get high tds readings after changing out the membrane?

[bioneck47]

also, I did change out the resin...

[dots]

Let it run a bit and try testing it again.

[Toddrtrex]

Is the RO membrane all the way in the RO housing? It seems that the last 1/2 inch or so is a bit harder to get all the way in.

[Buckeye Hydro]

Could of things to check:
1. Did you allow the system to run for a couple of minutes before you took your TDS measurement?
2. Often when we help folks with this sort of problem the issue ends up being erroneous TDS readings because of the way they took the sample (bad meter, dirty sample container, reading tds creep water, etc). Check your techniqes...
3. Membrane not fully seated (allowing waste water to leak into the purified water port.
4. Cracked RO membrane housing (but you said you tried a new housing).

What is your pressure?

Russ @
Buckeye Field Supply

[luther1200]

It probably isn't seated correctly. I did the same thing once. Just push it in a little more. It helps if you wet the rubber O-rings first.

[bioneck47]

<a href=showthread.php?s=&postid=15274090#post15274090 target=_blank>Originally posted</a> by BuckeyeFS
Could of things to check:
1. Did you allow the system to run for a couple of minutes before you took your TDS measurement?
2. Often when we help folks with this sort of problem the issue ends up being erroneous TDS readings because of the way they took the sample (bad meter, dirty sample container, reading tds creep water, etc). Check your techniqes...
3. Membrane not fully seated (allowing waste water to leak into the purified water port.
4. Cracked RO membrane housing (but you said you tried a new housing).

What is your pressure?

Russ @
Buckeye Field Supply
I've let it run for about 3 hours now with the same results. I also put the old membrane back in and the TDS is reading 12. So I know that the meter is fine. I also pushed the membrane in as hard as I could to make sure that it is seated. I think that there is water leaking inside somewhere because the flow coming out is a little faster than normal. Maybe leaking around the brine seal?

[Buckeye Hydro]

Leaks around the brine seal would not generate what you are seeing. Think about leaks around the orings, or a cracked housing, or a bad membrane.

This is the RO water tds you are talking about, right?

Before you said it was 50, now its 12? !2 might not be bad depending upon your incoming tds and the specs on your membrane.

[Buckeye Hydro]

What is your pressure, and what is your feedwater tds?

[luther1200]

What is the incoming TDS? Is it getting better at all?

[bioneck47]

<a href=showthread.php?s=&postid=15277295#post15277295 target=_blank>Originally posted</a> by BuckeyeFS
Leaks around the brine seal would not generate what you are seeing. Think about leaks around the orings, or a cracked housing, or a bad membrane.

This is the RO water tds you are talking about, right?

Before you said it was 50, now its 12? !2 might not be bad depending upon your incoming tds and the specs on your membrane.
No, it's 12 with the old membrane. I know it's not the membrane because I actually purchased 2 other ones and they are all doing the same thing. And yes this is the ro tds that I'm talking about. It has now dropped to 44ppm so there has been a slight improvement but still kinda high.

Also I don't know what my exact pressure is. Where can I get a gauge other than online?

[Toddrtrex]

A shot in the dark.

What type of membrane did you buy? (( And don't say RO. ;) )). I am wondering if it isn't the right size --- though I have always thought there is only one size. Maybe is a just a touch too small and letting some water get around it.

[Buckeye Hydro]

<a href=showthread.php?s=&postid=15278762#post15278762 target=_blank>Originally posted</a> by bioneck47
No, it's 12 with the old membrane. I know it's not the membrane because I actually purchased 2 other ones and they are all doing the same thing. And yes this is the ro tds that I'm talking about. It has now dropped to 44ppm so there has been a slight improvement but still kinda high.

Also I don't know what my exact pressure is. Where can I get a gauge other than online?

44 is VERY high. What is your feedwater tds?

You're not likely going to find a pressure gauge KIT locally. You will be able to buy a gauge (be prepared for sticker shock from a local retail outfit!), but unlikely you'll find the quick connect fittings you want.

I suspect you either have very low pressure or a bad membrane housing.