RO/DI Mystery

JoeyBagadonuts

JoeyBagadonuts

Member
Hey Everyone, hoping someone might be able to help me out. I have searched, exhaustingly, online for an answer and still cant figure it out. Soooo, before I throw more money at it...

Current setup is:

Sediment
.6 Micron Matrikx CTO Carbon Block
CSM 80gpd Membrane
DI Resin

I noticed the other day that my relatively new DI resin was already changing color. I'm not new to changing filters/maintenance to it. So I went to the LFS and got a PureT 1 Micron Carbon block, they didn't have a sediment filter, so I went to Lowes and got a Whirlpool 5 micron sediment filter. Rinsed both for a little while then tested TDS after RO. Coming out at 30ish. Figured that the membrane (Axeon 100gpd) was bad so went to another LFS and got CSM 80gpd. Took old one out, cleaned housing, put new in, and flushed membrane for an hour. Took TDS after RO, 30ish still!!! ***?

Yes, I made sure membrane was seated correctly and housing does not looked cracked. (Actually tried other housing I have with same result)

How can I have exact same TDS after new membrane? Anyone have any idea where the failure is?

My tap is 260is, so rejection rate on both new and old membranes is about 88%. Makes sense for the old Axeon but to get the same for the brand new one drives me nuts. Spec sheet for CSM says it should be starting out at least 96%. :debi:

Please let me know if you have experienced this and what you did to correct!

Thank you!
 
Joey,
Since you are experiencing this my take is to get a new membrane from one of the RO guys here on RC where you have some recourse if it does not perform to specs.
OR, go back to the store & tell them your story & see if they will give you a new one that also might be NG if from the same batch.
Sometimes you just have to buy from the "right" supplier.
 
Water pressure is good. Over 70 psi but I run it at 60 according to the pressure gauge on the unit.
Not on well water. City of Tarpon Springs water.
Never had this issue when changing membranes before.
 
Vinny,

My next step is to do that and either get a replacement from them or order a Dow Filmtec or Spectrapure membrane. I am just trying to figure out if there is something I am missing before going through the hassle and getting the same result. I hear what you are saying about the "right" supplier. I will see if/what the LFS I got it from will do about it.
 
I do believe though that the flow restrictor must match the membrane size or you will have problems..

Give buckeye hydro a call on the phone and discuss it..
Tell them reef central sent you to them and they will help walk you through it and get you any needed parts,etc..
http://www.buckeyehydro.com/
 
Thanks Mcgyvr.

I do have a combo flush valve/restrictor on the waste line that has 600 on it. From what I have seen for the membrane recommended is 550. I can see what Buckeye says.
 
Scuzy,
Not sure what you mean by break?

Kennytze,
I thought my handheld might be an issue but I tested it with some water that I had made previously and it read 0 TDS.
 
Chloramine getting through your membrane thus eventually killing the membrane. Chloramine is bad for membranes.


Sent from my iPhone using Tapatalk Pro
 
JoeyBagadonuts said:
...
My tap is 260is, so rejection rate on both new and old membranes is about 88%. Makes sense for the old Axeon but to get the same for the brand new one drives me nuts. Spec sheet for CSM says it should be starting out at least 96%....
Click to expand...

Pretty sure that's "as high as 96%..." with a big emphasis on "as high as". Your mileage may vary, depending on temperature, pressure, blah blah blah. 90% rejection seems very reasonable.

Looking at the water quality reports for Tarpon Springs, looks like they use both chlorine and/or chloramine to disinfect the water. In the chart showing what they've found in the water, there are traces of chloramines shown. Might want to touch base with your water company to confirm what they're using *right now*. As noted earlier, chloramines and RO membranes don't play nice. A carbon block will remove chlorine, but not chloramines.

But still... 90% isn't bad.
 
I just got off the phone with our city water department. They use only free chlorine. We have a big RO water treatment plant that opened a little over a year ago. I thought maybe it could have been chloramine but this rules it out. I would think that my new carbon block should be good for just free chlorine.

Has anyone had a new membrane that started out a little high then came down?
 
kurt_n said:
Pretty sure that's "as high as 96%..." with a big emphasis on "as high as". Your mileage may vary, depending on temperature, pressure, blah blah blah. 90% rejection seems very reasonable.

Looking at the water quality reports for Tarpon Springs, looks like they use both chlorine and/or chloramine to disinfect the water. In the chart showing what they've found in the water, there are traces of chloramines shown. Might want to touch base with your water company to confirm what they're using *right now*. As noted earlier, chloramines and RO membranes don't play nice. A carbon block will remove chlorine, but not chloramines.

But still... 90% isn't bad.
Click to expand...

A carbon block will break down chloramines.
 
90% is not acceptable for a new membrane. You should be it the 95% or above range for several years with a quality membrane. I would test your waste to good water ratio and make sure it is 4 to 1. If not then you need to adjust your flow restrictor if you can. If not then you need to get one that is matched to your membrane's gpd.
 
I appreciate the help from everyone. So it turns out that I either won the lottery and got a bad membrane or it got fried somehow. I took a chance and bought a new Dow Filmtec membrane and put it in. I now have 10 TDS after RO. 96% rejection rate. That is acceptable. Next filter changes I will talk to you guys Russ.

Thanks everyone!
 
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