40 TDS after New RO Membrane?

[mstgkillr]

I won a, I forget the name, RO/DI system at MACNA. After correctly flushing the RO membrane and then installing the DI resin, I was only able to make about 45 gallons of DI water before going through all of the DI resin. I assumed that it was just a cheap RO/DI system and low supply water pressure.

Recently, I picked up a used IceCap 4 Stage Smart RO/DI system, which includes a booster pump. Although the unit was only a year old and performing perfectly for the previous owner, when I installed the system, I was seeing 35-40 TDS after the RO membrane. I decided to replace all of the filters and RO membrane. I used a brand new AquaFX 1 micron sediment filter, AquaFX 5/10 carbon block, and Dow FilmTec 75 GPD BW60-1812-75 RO membrane (99% rejection rate). After flushing the RO membrane, I see no improvement and still getting 35-40 TDS after the RO membrane.

Obviously, I would use way too much DI resin with a 35-40 TDS. It appears that something is not functioning correctly.

Any help would be greatly appreciated!

RO/DI System Source Water
TDS = 550 ppm
Hardness = <1 grain per gallon (after a large water softener)
Pressure = 40-60 PSI, but the booster pump brings it up to 80-90 PSI

 

[OA3B]

Sorry to hear this...
I’m recovering from this issue myself. I changed out my membrane like you have done. I changed the sediment and carbon and also added another carbon filter. Using one DI filter, gave me a zero tds reading. This can be a frustrating part of the hobby but take your time to double and maybe triple check to make sure the filters are seated properly and no channeling is happening. GL!!

 

[I.AM.MR.MIKE]

I have a very similar issue. Same exact membrane in brand new Typhoon 5 running GAC in place of first carbon due to chloramines. Membrane verified with Dow app to be genuiune.

Pressure 50 PSI
Water temp 57.2 f
Tap TDS 272
Unit comes with a 800 flow restrictor
Appears to be dumping 3 gallons for every one gallon pure

After membrane 18 - 20 after flushing and then running for 8 hours (started at 27)
1)10 micron sed filter
2)refillable activated carbon
3)1 micron carbon block
4)BW60-1812-75 RO membrane
5)refillable DI resin

Old unit was a RODI Buddie with a vontron 50gpd and got a similar rejection rate of 93%. I was expecting 97-99 with dow.

 

[Blue Spot Octopus]

Watch the BRS videos on how to use and improve your RO/DI machine,https://www.marinedepot.com/reverse-osmosis/replacement-filters/tfc-membranes
make sure this membrane is fully seated, push really hard.

 

[mtfish]

You have to have a booster pump unless your regular water pressure is really high. 75 to 80 psi is what to shoot for. As stated, make sure your membranes are properly seated. Use silicon grease helps make sure seal does not leak. Your RO membrane has spcecs. Usually 95 to 98% rejection. For example. Say incoming TDS is 100 your output water should be 2 using 98% filter. If you don't get this ratio, then take everything apart and put back together again. Hope you figure it out.

 

[mstgkillr]

I just heard back from Coralvue/IceCap, through a support ticket that I created. They recommended adding a sediment prefilter, which makes no sense as I already have a 1 micron sediment filter. I was able to reduce the post RO TDS to 20 swapping out the 550 flow restrictor to an 800, but now I have more wastewater.

 

[I.AM.MR.MIKE]

I have a very similar issue. Same exact membrane in brand new Typhoon 5 running GAC in place of first carbon due to chloramines. Membrane verified with Dow app to be genuine.

Pressure 50 PSI
Water temp 57.2 f
Tap TDS 272
Unit comes with a 800 flow restrictor
Appears to be dumping 3 gallons for every one gallon pure

After membrane 18 - 20 after flushing and then running for 8 hours (started at 27)
1)10 micron sed filter
2)refillable activated carbon
3)1 micron carbon block
4)BW60-1812-75 RO membrane
5)refillable DI resin

Old unit was a RODI Buddie with a vontron 50gpd and got a similar rejection rate of 93%. I was expecting 97-99 with dow.

I changed to a 1 Micron GE Z sed cart and a 550 flush/flow restrictor. I also installed a new gauge on the input to the membrane. Results: Water pressure is actually 65 plus. No real change in TDS results. Less waste water.

 

[CoralFan1776]

Those numbers do seem to high.
I have well water that measured 550-680 or so coming into the RO filter which is after a whole house water softener. It varies over the course of a year. I don't know why.
I use the pump buddy for pressure boost and automated membrane flush.
I have the following custom RO/DI setup.
1. 5 micron sediment filter.
2. .5 micron carbon block.
3. .5 micron carbon block.
4. RO membrane.
This is then fed into a RO pressure tank that feeds the whole house (refrigerator, sink spigot) and also to my DI setup for the fish tank.
The DI is first Cation, then Anion, and finally a mixed bed cartridge.
This is basically what BRS outlined in one of their videos.
I get 11-19 TDS out of the RO membrane and 0 after the DI cartridges. 11 out of the membrane with 550 in is a 98 percent rejection rate so I consider that good.

I haven't replaced the Cation yet and this DI setup has been installed for about 1 year with no color change at all yet.
The Anion is another story. I originally had the standard 2.5 x 10 inch refillable cartridge but I soon replaced that with a 2.5 x 20 inch refillable cartridge so I wouldn't have to change it out so often.
The final mixed bed cartridge I think I've changed twice since it was setup and both times it was because I didn't catch the Anion before it was completely exhausted and it degraded the mixed bed because of it.
If I replace the Anion before it is completely exhausted I would bet I would be able to get a year out of the mixed bed.

I've read that the most likely problem causing the Anion to be exhausted more quickly is high CO2 in the source water.
If that is correct you can bubble air through the water before you run it through the DI to blow the CO2 off and extend the life of your Anion DI. I don't have a convenient way of doing that so I don't.
I've never measured how much water I'm getting through that 2.5 x 20 inch cartridge before I have to replace the media but I would guess 150-200 gallon.

If you aren't getting at least 97 percent rejection rate from source water to after the RO membrane and you have 50 PSI or more then something is wrong IMO.
Always double triple check the basic plumbing. It can be pretty easy to get tubing misrouted.
Also make sure you have the right size flow restrictor for your membrane.
I like the pump buddy. I bought it from marine depot about 5 years ago and it has worked well.
I get about 90PSI out of it and it does the membrane flush every time it starts up.

Good luck!
If you get the TDS down be sure and let us know what did the trick.

 

[adrianr514]

What is your rejection rate at? You may need a lower rejection rate. When I was running a 1:1 rejection I was getting around 31ppm and when I lowered it to 1:4 with a ball valve I am getting 8ppm.

 

[I.AM.MR.MIKE]

It hasn't really improved. I have tried an 800 that it came with and a 550 restriction - no real change. Maybe the 50-55 degree water this time of year is causing this? I am thinking it is the membrane as I have read a lot of reports of people complaining and they have this membrane in common.
BW60-1812-75

 

[I.AM.MR.MIKE]

mistake post

 

[robbyg]

This is antidotal advice but one time I bought a Dow membrane and inserted it and I think within minutes it cracked the filters fibers. After that I always soak them overnight in bucket so that the material is more pliable before pressure is put on it.

 

[Ancient Aviator]

I had the same issue with really bad numbers AFTER changing everything: the sediment filter, carbon filter, DI canister and membrane. I flushed them all properly during the change-out. It just didn't make sense.

I removed each filter to inspect and re-seated each properly. They looked fine. However upon removing my DI filter I found it had NOT seated properly when I first installed it, and I had severely damaged the top seal/washer on the DI cartridge. I'm sure water was just bypassing the DI cartridge...or at least a lot of water was, thus giving me the HI TDS numbers. I ordered a replacement pre-packed DI cartridge BRS. So...it was operator error...I created the problem by not properly seating the DI cartridge inside the canister.

My RO/DI unit "leans" downward from its own weight, so it's difficult to properly seat the filters/cartridge without supporting the entire unit to KEEP IT LEVEL during the install. I've since devised a support to do that while I'm doing maintenance on the unit. It makes a HUGE difference...SO much easier to get the cartridges and filter properly seated!