RO/DI question

HWDylan · 12/04/2012, 06:25 PM

So I have the BRS Value Plus RO/DI unit and it works great. I purchased the float valve with it so I do not overflow my reservoir (32 Brute). I have the input hooked up to a garden hose spigot I installed in my basement so that I can turn the water on and off if I need to and I have the drain plugged into a drain pipe.

My question is:

Because I have both the float valve and the back flow valve (comes with the BRS Value Plus) I can basically leave the water to the system turned on all the time so that when I use a little water it fills back up automatically. Is this bad to do? I seem to be eating through my DI resin very quickly and I was wondering if that was why. My house pressure is about 65PSI, does it cause any extra wear and tear on the system to have the water to the unit turned on 24/7?

sleepydoc · 12/04/2012, 06:45 PM

you can, the concern I would have is if the float valve should fail, you would have a mess. You can get an additional auto shutoff valve from BRS that gives and additional measure of safety.

I try to shut off my main supply when I'm not using the system, just to be safe.

Mark Bianco · 12/04/2012, 06:57 PM

Another issue is generally the first 5minutes of the water coming out of the DI unit will have a high TDS reading and by all rights should be thrown away. For some reason after water sits in the RO/DI unit it goes bad. I have no idea why perhaps someone that has more knowledge can chime in.

Mark

ryeguyy84 · 12/04/2012, 07:45 PM

Quote:

Originally Posted by Mark Bianco

Another issue is generally the first 5minutes of the water coming out of the DI unit will have a high TDS reading and by all rights should be thrown away. For some reason after water sits in the RO/DI unit it goes bad. I have no idea why perhaps someone that has more knowledge can chime in.

Mark

0tds should always come out of the di resin. The higher tds comes out of the to stage

sleepydoc · 12/04/2012, 08:58 PM

Quote:

Originally Posted by Mark Bianco

Another issue is generally the first 5minutes of the water coming out of the DI unit will have a high TDS reading and by all rights should be thrown away. For some reason after water sits in the RO/DI unit it goes bad. I have no idea why perhaps someone that has more knowledge can chime in.

As ryeguy said, the DI output should always be 0 TDS. The issue is that the RO membrane takes a bit to 'start up,' and the RO water produced for the first few minutes has a significantly higher TDS. This usually corrects fairly quickly, but I have Tee with a valve between my RO and DI stages. When I first start it up, I open it up and toss the water that first comes out to extend the life of my DI resin.

Mike31154 · 12/04/2012, 10:15 PM

My tap TDS is 210+ on any given day. Whenever I've monitored the TDS coming out of the 75gpd membrane in my system immediately after turning the water on, it rises to well over 110 TDS, peaks there & takes about 5 minutes to drop down to 1. I also have a tee between the RO membrane & DI stage and I use this to divert this initial high TDS product water into a waste container. It ends up being about a half gallon that gets dumped.

In your case, where your system is always on, running for short bursts based on demand from your float valve, you don't get optimal performance out of your RO membrane since it never gets the chance to bring the TDS down to where it won't deplete your DI resin in short order, as you are experiencing. Your intermittent, short top-ups more than likely run very high TDS through your DI stage. Water production is best accomplished into a separate reservoir filled less frequently with longer production runs. Can't argue with the convenience of doing it your way, but you'll continue to burn through DI at a faster rate than is necessary & DI resin is one of the costlier consumables when it comes to RODI systems.

I simply can't get myself to trust not flooding the basement by having my RODI system under pressure 24/7. I like to be home when producing RODI and generally make about 5 gallons of RO water for drinking, making wine, beer, soda pop, etc. This takes 45 minutes and only then do I divert the water to the DI stage to make my top up water. This ensures the TDS going to the DI stage is as low as it can get, usually 1 TDS and always 0 TDS out of the DI. My first container of DI resin lasted just over 3 years this way, after producing some 2,300 gallons of DI water (I use an Excel spreadsheet to keep track of production).

HWDylan · 12/05/2012, 12:55 AM

Thanks for the input guys.

I asked this same question to BRS and the answer I got was a bit ambiguous. I knew there was a TDS creep when you are not using the system but I was unaware how this actually affected my product (or DI resin in this case). I have the flush valve installed on my system (came with it already installed) so you guy recommend that I run the system for 5ish min through the flush valve before each run?

The reason I was doing it this way is because it is convenient and I have my RO reservoir sitting over a drain so even if my float valve fails I still don't have a flooded basement.

I guess from now on I will flush for 5min before and then make a whole barrel of water at once. Less convenient but I ate through this DI resin in like 2 weeks and my house water is really low TDS (007ppm) so I figured I was doing something wrong.

ryeguyy84 · 12/05/2012, 06:01 AM

Your tap water is 7tds? Do you live in Alaska next to a clear blue lake?

My tap water is 450ish. It makes me wonder what's in there. I get between 5 and 7 coming out of my RO.

Palidora5 · 12/05/2012, 06:19 AM

yea its good a good thing to get in habbit of doing. flushing the membrane extends thwe life of the mebrane and you di resin. i flush it almost everytime for like 2 mins di resin still get sucked up in my system though

Mike31154 · 12/05/2012, 11:14 AM

Flushing, yes, forgot to mention I do that as well. About a minute or so before & after each run.

If your incoming TDS is really that low (007) on a consistent basis, you might consider using DI only. Get a larger DI stage or run a couple in series with perhaps a very fine sediment & carbon stages up front. You'd have to do the math as to whether the cost of water outweighs the cost of DI media. Depends on what you pay for water, but using DI only you would not be sending any water down the drain.

Alternatively, with 007 TDS you should easily be getting 0 out of your membrane.... Mr. Bond, James Bond....time for a martini now..

Wmich2008 · 12/05/2012, 11:19 AM

Quote:

Originally Posted by ryeguyy84

Your tap water is 7tds? Do you live in Alaska next to a clear blue lake?

My tap water is 450ish. It makes me wonder what's in there. I get between 5 and 7 coming out of my RO.

450! Dang I get between 4-10 coming in and I thought that was high.

Michigan Mike · 12/05/2012, 11:27 AM

007? Wow...Something isn't right.
My TDS out the tap is 150 and is 1 going into the DI, I flush before and after each use for a minute or two.
I would look into other options if my TDS was that low. You need more info about your water. There has to be something wrong. I would look into another , less wasteful way of bettering your water quality (if you even need to) without wasting water if its that good already.

whitemarlin · 12/05/2012, 11:50 AM

If you are on well water its probably co2 in the water, and you are going to have to degas the water before running it thru the DI. co2 will exhaust the DI resin rather quickly.

Wmich2008 · 12/05/2012, 12:40 PM

Well I had a plumber hook it up so i guess it goes through the house ro first then to my bulk reef supply ro/di unit.

Wmich2008 · 12/05/2012, 12:45 PM

You think With 007 tds you could just run it straight to the tank? I thought 0tds was ideal

HWDylan · 12/05/2012, 01:51 PM

Ok so I looked into it a bit since you guys were all shocked by my low TDS water. I think I told you the wrong thing. I am in the process of still figuring this all out so I am a bit ... dumb haha.

That TDS reading is what my TDS meter says when I switch it to "IN". I looked at all of the connections though and I now see that the 'IN" reading is the water going into the DI not into the whole unit. I also noticed that if I leave the water to the system on but I am not producing water because of the valve shut offs, that "IN" reading goes way up into the 170s. That must be the TDS creep people are talking about. That would explain why my DI resin only lasted me a few weeks. My "OUT" water is still 000TDS but since my resin is all brown now (color changing resin) I am starting to see 001TDS every once and a while. I have some more resin coming.

Is there any way to combat this and make my resin last longer? I am in the process of setting the tank up and curing rocks right now so I am using tons of water and I know that will change once I get the tank actually running, but is there anything I should do to help keep my resin from burning up like that?

12/04/2012, 06:25 PM	#1
HWDylan Registered Member Join Date: Oct 2012 Location: St. Louis Posts: 64	RO/DI question So I have the BRS Value Plus RO/DI unit and it works great. I purchased the float valve with it so I do not overflow my reservoir (32 Brute). I have the input hooked up to a garden hose spigot I installed in my basement so that I can turn the water on and off if I need to and I have the drain plugged into a drain pipe. My question is: Because I have both the float valve and the back flow valve (comes with the BRS Value Plus) I can basically leave the water to the system turned on all the time so that when I use a little water it fills back up automatically. Is this bad to do? I seem to be eating through my DI resin very quickly and I was wondering if that was why. My house pressure is about 65PSI, does it cause any extra wear and tear on the system to have the water to the unit turned on 24/7?

12/04/2012, 06:45 PM	#2
sleepydoc Registered Member Join Date: Oct 2011 Location: Minneapolis, MN Posts: 3,907	you can, the concern I would have is if the float valve should fail, you would have a mess. You can get an additional auto shutoff valve from BRS that gives and additional measure of safety. I try to shut off my main supply when I'm not using the system, just to be safe. __________________ ~~~~~~~~~~~~~~~~~~~~~ 120 gallon, coast to coast overflow w/beananimal overflow. Waveline DC 10000 II return pump, 40 gal sump, Octopus XS200 skimmer, T5 lighting

12/04/2012, 10:15 PM	#6
Mike31154 Registered Member Join Date: Apr 2008 Location: B.C. Canada Posts: 1,555	My tap TDS is 210+ on any given day. Whenever I've monitored the TDS coming out of the 75gpd membrane in my system immediately after turning the water on, it rises to well over 110 TDS, peaks there & takes about 5 minutes to drop down to 1. I also have a tee between the RO membrane & DI stage and I use this to divert this initial high TDS product water into a waste container. It ends up being about a half gallon that gets dumped. In your case, where your system is always on, running for short bursts based on demand from your float valve, you don't get optimal performance out of your RO membrane since it never gets the chance to bring the TDS down to where it won't deplete your DI resin in short order, as you are experiencing. Your intermittent, short top-ups more than likely run very high TDS through your DI stage. Water production is best accomplished into a separate reservoir filled less frequently with longer production runs. Can't argue with the convenience of doing it your way, but you'll continue to burn through DI at a faster rate than is necessary & DI resin is one of the costlier consumables when it comes to RODI systems. I simply can't get myself to trust not flooding the basement by having my RODI system under pressure 24/7. I like to be home when producing RODI and generally make about 5 gallons of RO water for drinking, making wine, beer, soda pop, etc. This takes 45 minutes and only then do I divert the water to the DI stage to make my top up water. This ensures the TDS going to the DI stage is as low as it can get, usually 1 TDS and always 0 TDS out of the DI. My first container of DI resin lasted just over 3 years this way, after producing some 2,300 gallons of DI water (I use an Excel spreadsheet to keep track of production). __________________ Mike Current Tank Info: 77g sumpless sw with rock, sand, a few critters, fishes & polyps. Lights, pumps.....

12/05/2012, 06:01 AM	#8
ryeguyy84 Registered Member Join Date: Mar 2011 Location: New Jersey Posts: 2,753	Your tap water is 7tds? Do you live in Alaska next to a clear blue lake? My tap water is 450ish. It makes me wonder what's in there. I get between 5 and 7 coming out of my RO. __________________ Current tank: 90G mixed reef. Current Tank Info: 90 gallon

12/05/2012, 06:19 AM	#9
Palidora5 Registered Member Join Date: Mar 2012 Posts: 54	yea its good a good thing to get in habbit of doing. flushing the membrane extends thwe life of the mebrane and you di resin. i flush it almost everytime for like 2 mins di resin still get sucked up in my system though __________________ 150 gallon dt 55 gallon sump

12/04/2012, 06:57 PM	#3
Mark Bianco In Memoriam Join Date: Nov 2011 Location: Infinity and Beyond Posts: 2,445	Another issue is generally the first 5minutes of the water coming out of the DI unit will have a high TDS reading and by all rights should be thrown away. For some reason after water sits in the RO/DI unit it goes bad. I have no idea why perhaps someone that has more knowledge can chime in. Mark

12/05/2012, 12:55 AM	#7
HWDylan Registered Member Join Date: Oct 2012 Location: St. Louis Posts: 64	Thanks for the input guys. I asked this same question to BRS and the answer I got was a bit ambiguous. I knew there was a TDS creep when you are not using the system but I was unaware how this actually affected my product (or DI resin in this case). I have the flush valve installed on my system (came with it already installed) so you guy recommend that I run the system for 5ish min through the flush valve before each run? The reason I was doing it this way is because it is convenient and I have my RO reservoir sitting over a drain so even if my float valve fails I still don't have a flooded basement. I guess from now on I will flush for 5min before and then make a whole barrel of water at once. Less convenient but I ate through this DI resin in like 2 weeks and my house water is really low TDS (007ppm) so I figured I was doing something wrong.

12/05/2012, 11:14 AM	#10
Mike31154 Registered Member Join Date: Apr 2008 Location: B.C. Canada Posts: 1,555	Flushing, yes, forgot to mention I do that as well. About a minute or so before & after each run. If your incoming TDS is really that low (007) on a consistent basis, you might consider using DI only. Get a larger DI stage or run a couple in series with perhaps a very fine sediment & carbon stages up front. You'd have to do the math as to whether the cost of water outweighs the cost of DI media. Depends on what you pay for water, but using DI only you would not be sending any water down the drain. Alternatively, with 007 TDS you should easily be getting 0 out of your membrane.... Mr. Bond, James Bond....time for a martini now.. __________________ Mike Current Tank Info: 77g sumpless sw with rock, sand, a few critters, fishes & polyps. Lights, pumps..... Last edited by Mike31154; 12/05/2012 at 11:20 AM.

12/05/2012, 11:27 AM	#12
Michigan Mike Freedom costs a buckofive Join Date: May 2012 Location: Michigan Posts: 3,002	007? Wow...Something isn't right. My TDS out the tap is 150 and is 1 going into the DI, I flush before and after each use for a minute or two. I would look into other options if my TDS was that low. You need more info about your water. There has to be something wrong. I would look into another , less wasteful way of bettering your water quality (if you even need to) without wasting water if its that good already.

12/05/2012, 11:50 AM	#13
whitemarlin Registered Member Join Date: Oct 2011 Posts: 96	If you are on well water its probably co2 in the water, and you are going to have to degas the water before running it thru the DI. co2 will exhaust the DI resin rather quickly.

12/05/2012, 12:40 PM	#14
Wmich2008 Registered Member Join Date: Feb 2012 Location: Battle creek Michigan Posts: 536	Well I had a plumber hook it up so i guess it goes through the house ro first then to my bulk reef supply ro/di unit.

12/05/2012, 12:45 PM	#15
Wmich2008 Registered Member Join Date: Feb 2012 Location: Battle creek Michigan Posts: 536	You think With 007 tds you could just run it straight to the tank? I thought 0tds was ideal Last edited by Wmich2008; 12/05/2012 at 01:05 PM.

12/05/2012, 01:51 PM	#16
HWDylan Registered Member Join Date: Oct 2012 Location: St. Louis Posts: 64	Ok so I looked into it a bit since you guys were all shocked by my low TDS water. I think I told you the wrong thing. I am in the process of still figuring this all out so I am a bit ... dumb haha. That TDS reading is what my TDS meter says when I switch it to "IN". I looked at all of the connections though and I now see that the 'IN" reading is the water going into the DI not into the whole unit. I also noticed that if I leave the water to the system on but I am not producing water because of the valve shut offs, that "IN" reading goes way up into the 170s. That must be the TDS creep people are talking about. That would explain why my DI resin only lasted me a few weeks. My "OUT" water is still 000TDS but since my resin is all brown now (color changing resin) I am starting to see 001TDS every once and a while. I have some more resin coming. Is there any way to combat this and make my resin last longer? I am in the process of setting the tank up and curing rocks right now so I am using tons of water and I know that will change once I get the tank actually running, but is there anything I should do to help keep my resin from burning up like that? Last edited by HWDylan; 12/05/2012 at 01:58 PM.