Ro filter problem I can't find an answer to

[Felstmiester]

Hi guys. I'm hoping someone can help.

I'm stumped with this Ro filter scenario
Put new cartridges in last week. Micron & carbon cartridges brought off eBay & membrane purchased from a reputable local lfs.
Installed all and ran well over 25ltrs through. TDS tested at over 100. Removed all cartridges several times to check there was no bypass but to no avail. Ran around 100ltrs and still reading 100. Gave up as was going away for weekend and assumed it was my hand held TDS metre buggered.

Went and tested my pen and it's balls on accurate so brought another micron & carbon cartridge ( original D&D ) as this was the only thing I could think may be the problem ( cheap cartridges off eBay )
Flushed, ran over 30 ltrs. Still reading 100!!!!!!!!

TDS
Tap 415
After micron & carbon filters 409
After all 3 it's 100
Only thing I can think is it could be the membrane?

I have got a Di pod as well but thought it's pointless fitting until I can find out why reading is so high.

I've now had it running product water constantly since Wednesday morning. It very slowly came down. Wednesday afternoon at 16:00 TDS was 65. Thursday ( yesterday ) at same time tds was 40. It then really slowed down and at 22:00 it was still at 40. I then decided to flush it for 10 mins thinking it might help it. No!! This morning ( Friday) it's now at 48.

Only thing I can think is the new ro membrane might be faulty???

Can't find anything on the net that relates to my problem. Never had to run an Ro filter this long in the past to see a tds reading of high 40's

 

[Rafty]

Must be RO membrane. You have presumably run into a cup for testing rather than testing from collection container.


Sent from my iPhone using Tapatalk

 

[reefgeezer]

1. Bad RO Membrane
2. Membrane o-ring not seated in back of housing
3. Pressure valve fail on RO water output line

 

[Felstmiester]

Yes. Always tested in a clean cup/glass

 

[Felstmiester]

1. Bad RO Membrane
2. Membrane o-ring not seated in back of housing
3. Pressure valve fail on RO water output line

When you say pressure valve do you mean the flush valve on the waste water side as that's all mine has ever had.

 

[reefgeezer]

When you say pressure valve do you mean the flush valve on the waste water side as that's all mine has ever had.

No. I'm not 100% how it works, but mine failed and I had to replace it. There is a valve either in the hose fitting screwed into the membrane housing or in-line in the RO water output line. I think it increases the pressure to force water through the membrane.

Also, if you haven't got the o-ring in the back of the membrane seated, the RO output will be more than normal because water is bypassing the membrane.

 

[Felstmiester]

I'm pretty sure mine hasn't got that. It's a D&D 3 stage.
I'm 100% that all the seals, o rings are ok. And it's definitely seated in properly because I've checked everything over 10 times. I'm hoping it's a bad new membrane. Fingers crossed

 

[on the spot]

I'd bet the membrane was fine, but isn't suited to your current flow restrictor.


HTH

 

[wrott]

Yes, flow.restrictor not correct for gph for membrane.
Or, ro membrane not seated.
Or, bad membrane.

What is the gph of your membrane and restrictor(located on waste water line).

 

[Felstmiester]

Yes, flow.restrictor not correct for gph for membrane.
Or, ro membrane not seated.
Or, bad membrane.

What is the gph of your membrane and restrictor(located on waste water line).

75gpd and all I can see on flow tap on waste line is it says 400??

 

[Opus123]

Assuming you bought a 75gpd membrane, your flow restrictor is correct. I would suggest testing to see what your good vs waster water ratio is at. Let the waste water collect in a a container you can measure and also do the same for the good water. Let them run for a set amount of time, say 5 minutes. Then compare the amount of water you get in each. You should have around 3 times more waste water vs good water. If your ratio is ok then I would say you just have a bad membrane. If the ratio is way off, then your restrictor may be going bad.

 

[moondoggy4]

https://www.marinedepot.com/reverse-osmosis/replacement-filters/tfc-membranes Make sure that this one is firmly seated. Watch the BRS videos on RO/DI.