BRS rodi 6 stage w/upgrade RO and booster pump -- high TDS

125mph · 01/10/2017, 11:30 PM

I've been running the BRS 6 stage rodi 75gpd for 5 years. Pressure has always been low, about 38psi. From that system, it hit average of 10-12 TDS exiting RO before DI. Tap water is 450-550 TDS.

I just upgraded to BRS watersaver 150gpd with dual membrane. I also added a booster pump which gets me to 85psi. My TDS is now 15 exiting RO.

I thought I was suppose to get much lower TDS with the booster pump? I know the dual membrane will result in higher TDS though. I've run the system for over 2 hours with no changes to TDS. I thought maybe breakin period? This is going to eat up di resin...

Good news is the output water is coming so fast!

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lngliv3 · 01/10/2017, 11:46 PM

How old is ur di resin?

125mph · 01/10/2017, 11:52 PM

Brand new. TDS is zero after DI canisters.

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Ou8me2 · 01/11/2017, 01:08 AM

So did you get new RO membranes? It's my understanding and it varies per maker. That you need to let it run for 30-60 minutes on new RO Membrane because of stuff they treat them with *can't remember the name* and discard that water. Sorry didn't know if you replaced them so it may not even apply.

Also using your figures and I just used a 500 avg on incoming TDS.

To figure it you need the incoming TDS plus the TDS after the RO so like this:

500 -15 = 485
485 divided by 500 = .97 = 97% So your RO membrane is rejecting 97% of the TDS.

This is the way Russ at Buckeye Hydro showed me how to figure it. I can not say if increasing the pressure will help the RO TDS or not and that would be a question for an expert which isn't me. Also how long are you running before measuring TDS? Might be TDS creep which can occur within the first minute or two minutes. Basically, when water sits in the membrane housing for a duration, TDS rises as it wicks out of the membrane.

xREEFINaintEZx · 01/11/2017, 08:57 AM

Yea your @ 97%. That's good. I run my duals at 60 and they are running @97

125mph · 01/11/2017, 11:00 AM

Awesome! Thanks. I thought some people were getting as low as 1-2TDS but then I checked my source water and realized it was high TDS.

Skim · 01/11/2017, 11:12 AM

I would say that your original membrane is shot and you should have bought a new when you purchased the water saver kit. Try putting the old membrane first going into the new and if you see a drop in TDS you old membrane is shot. I have the BRS 6 Stage with water saver. Membranes coming up to 2 years and I still get 99% rejection, I would do a little more investigating, I believe you should be getting better numbers.

Pablos RSM 450 · 01/11/2017, 11:20 AM

Quote:

Originally Posted by 125mph

Awesome! Thanks. I thought some people were getting as low as 1-2TDS but then I checked my source water and realized it was high TDS.

Bro the thing is that the water saver is made to run with lower TDS acording to the BRS video. It is not recommended for TDS above 300.

https://youtu.be/GE0Dhp5DZv8

Skim · 01/11/2017, 12:12 PM

My TDS varies from 340 to as high as 450 and I still get the 99% rejection. Yes and all TDS meters where re calibrated few months ago. I believe you should at least be in the 98% TDS of 8 or 7. I would just pick up a new Membrane as you ran it at a low psi, so most likely it is shot. The other thing that helps is Flushing for a few minutes after every use.

Ou8me2 · 01/11/2017, 04:19 PM

97% is not that bad and even before when he was getting lower TDS he was just a hair more efficient at 97.6% and with his very high incoming TDS that's probably about the best he will do. 450-550 TDS is a huge difference and not in a good way. I'm not sure if he replaced the old RO membrane but probably should have that way you start out with all fresh membranes.

LPS_Blasto · 01/11/2017, 05:04 PM

Quote:

Originally Posted by 125mph

I've been running the BRS 6 stage rodi 75gpd for 5 years. Pressure has always been low, about 38psi. From that system, it hit average of 10-12 TDS exiting RO before DI. Tap water is 450-550 TDS.

I just upgraded to BRS watersaver 150gpd with dual membrane. I also added a booster pump which gets me to 85psi. My TDS is now 15 exiting RO.

I thought I was suppose to get much lower TDS with the booster pump? I know the dual membrane will result in higher TDS though. I've run the system for over 2 hours with no changes to TDS. I thought maybe breakin period? This is going to eat up di resin...

Good news is the output water is coming so fast!

Sent from my iPhone using Tapatalk

I have a couple questions about RO units.

Why does running dual membranes result in higher TDS?

What happens if I don't run 2 minutes of water down the drain before filling the tank, bucket, reservoir etc?

I'm getting back into the hobby after taking four years off. I used to have 2 reefs and a frag tank. .

I was using a filter direct RO system. It was their 6 stage unit, and I added an additional membrane. I had their booster pump and my pressure was between 75-79psi. I broke it in for two hours before using. I had it set to automatically keep a 10g tank full (top off reservoir). It never ran for 2-3 minutes first.... when the tank had only an inch or two of water left, the RO unit turned on and filled the tank to within 1/2" of the top, then shut off automatically. Never ran 2 minutes of water down the drain first. I flushed it once or twice a month. It turned on, and refilled the 10g tank, about once every 4-5 days.

Am I doing this wrong, or has conventional wisdom changed in the last 4 years?

125mph · 01/11/2017, 05:09 PM

I think dual membranes plumbed as "Waste Water Saving" technique results in higher TDS in the second membrane because the waste water from one goes to the other.. something like that

.. what this video:

http://www.bulkreefsupply.com/video/...ow-To-Tuesday/

LPS_Blasto · 01/11/2017, 05:22 PM

Thanks!

tkeracer619 · 01/11/2017, 07:09 PM

What is the waste ratio?

01/10/2017, 11:30 PM	#1
125mph Registered Member Join Date: Apr 2011 Location: San Diego, CA Posts: 1,405	BRS rodi 6 stage w/upgrade RO and booster pump -- high TDS I've been running the BRS 6 stage rodi 75gpd for 5 years. Pressure has always been low, about 38psi. From that system, it hit average of 10-12 TDS exiting RO before DI. Tap water is 450-550 TDS. I just upgraded to BRS watersaver 150gpd with dual membrane. I also added a booster pump which gets me to 85psi. My TDS is now 15 exiting RO. I thought I was suppose to get much lower TDS with the booster pump? I know the dual membrane will result in higher TDS though. I've run the system for over 2 hours with no changes to TDS. I thought maybe breakin period? This is going to eat up di resin... Good news is the output water is coming so fast! Sent from my iPhone using Tapatalk __________________ 180G Rimless Starphire 72x24x24 (Miracles) 3 x Ecotech XR15w G4 Pro \| T5 x 4 \| 2 x Mp40wQD GEO 612 Cal Reactor \| Vertex Omega 150 Skimmer \| Chaeto Reactor Synergy Reef CL44 Sump \| Neptune Apex Last edited by 125mph; 01/10/2017 at 11:36 PM.

01/10/2017, 11:52 PM	#3
125mph Registered Member Join Date: Apr 2011 Location: San Diego, CA Posts: 1,405	BRS rodi 6 stage w/upgrade RO and booster pump -- high TDS Brand new. TDS is zero after DI canisters. Sent from my iPhone using Tapatalk __________________ 180G Rimless Starphire 72x24x24 (Miracles) 3 x Ecotech XR15w G4 Pro \| T5 x 4 \| 2 x Mp40wQD GEO 612 Cal Reactor \| Vertex Omega 150 Skimmer \| Chaeto Reactor Synergy Reef CL44 Sump \| Neptune Apex

01/11/2017, 01:08 AM	#4
Ou8me2 Registered Member Join Date: Feb 2016 Posts: 743	So did you get new RO membranes? It's my understanding and it varies per maker. That you need to let it run for 30-60 minutes on new RO Membrane because of stuff they treat them with can't remember the name and discard that water. Sorry didn't know if you replaced them so it may not even apply. Also using your figures and I just used a 500 avg on incoming TDS. To figure it you need the incoming TDS plus the TDS after the RO so like this: 500 -15 = 485 485 divided by 500 = .97 = 97% So your RO membrane is rejecting 97% of the TDS. This is the way Russ at Buckeye Hydro showed me how to figure it. I can not say if increasing the pressure will help the RO TDS or not and that would be a question for an expert which isn't me. Also how long are you running before measuring TDS? Might be TDS creep which can occur within the first minute or two minutes. Basically, when water sits in the membrane housing for a duration, TDS rises as it wicks out of the membrane. Last edited by Ou8me2; 01/11/2017 at 02:02 AM.

01/11/2017, 11:00 AM	#6
125mph Registered Member Join Date: Apr 2011 Location: San Diego, CA Posts: 1,405	Awesome! Thanks. I thought some people were getting as low as 1-2TDS but then I checked my source water and realized it was high TDS. __________________ 180G Rimless Starphire 72x24x24 (Miracles) 3 x Ecotech XR15w G4 Pro \| T5 x 4 \| 2 x Mp40wQD GEO 612 Cal Reactor \| Vertex Omega 150 Skimmer \| Chaeto Reactor Synergy Reef CL44 Sump \| Neptune Apex

01/11/2017, 05:09 PM	#12
125mph Registered Member Join Date: Apr 2011 Location: San Diego, CA Posts: 1,405	I think dual membranes plumbed as "Waste Water Saving" technique results in higher TDS in the second membrane because the waste water from one goes to the other.. something like that .. what this video: http://www.bulkreefsupply.com/video/...ow-To-Tuesday/ __________________ 180G Rimless Starphire 72x24x24 (Miracles) 3 x Ecotech XR15w G4 Pro \| T5 x 4 \| 2 x Mp40wQD GEO 612 Cal Reactor \| Vertex Omega 150 Skimmer \| Chaeto Reactor Synergy Reef CL44 Sump \| Neptune Apex

01/10/2017, 11:46 PM	#2
lngliv3 Registered Member Join Date: Oct 2016 Location: Toledo ohio Posts: 19	How old is ur di resin?

01/11/2017, 08:57 AM	#5
xREEFINaintEZx Registered Member Join Date: Aug 2016 Posts: 119	Yea your @ 97%. That's good. I run my duals at 60 and they are running @97

01/11/2017, 11:12 AM	#7
Skim Registered Member Join Date: Dec 2006 Location: Brantford ON. Canada Posts: 277	I would say that your original membrane is shot and you should have bought a new when you purchased the water saver kit. Try putting the old membrane first going into the new and if you see a drop in TDS you old membrane is shot. I have the BRS 6 Stage with water saver. Membranes coming up to 2 years and I still get 99% rejection, I would do a little more investigating, I believe you should be getting better numbers.

01/11/2017, 12:12 PM	#9
Skim Registered Member Join Date: Dec 2006 Location: Brantford ON. Canada Posts: 277	My TDS varies from 340 to as high as 450 and I still get the 99% rejection. Yes and all TDS meters where re calibrated few months ago. I believe you should at least be in the 98% TDS of 8 or 7. I would just pick up a new Membrane as you ran it at a low psi, so most likely it is shot. The other thing that helps is Flushing for a few minutes after every use.

01/11/2017, 04:19 PM	#10
Ou8me2 Registered Member Join Date: Feb 2016 Posts: 743	97% is not that bad and even before when he was getting lower TDS he was just a hair more efficient at 97.6% and with his very high incoming TDS that's probably about the best he will do. 450-550 TDS is a huge difference and not in a good way. I'm not sure if he replaced the old RO membrane but probably should have that way you start out with all fresh membranes.

01/11/2017, 05:22 PM	#13
LPS_Blasto Registered Member Join Date: Apr 2008 Posts: 581	Thanks!

01/11/2017, 07:09 PM	#14
tkeracer619 Registered Member Join Date: Jan 2006 Location: Westminster, CO Posts: 17,289	What is the waste ratio? __________________ Hobby Experience: 9200ish gallons, 26 skimmers, and a handful of Kent Scrapers. Current Tank: Vortech Powered 600G SPS Tank w/ 100gal frag tank & 100g Sump. RK2-RK10 Skimmer. ReefAngel. Radium 20k.