RO/DI water quality

tony098 · 02/26/2006, 07:36 PM

How can I check the quality of my RO unit's output? When I pour the water from the storage tank, the water has lots of microbubble and oily surface; this goes away if I let the water sits for couple minutes. Is this normal?

TitansFan · 02/26/2006, 07:37 PM

get a TDS meter.

BeanAnimal · 02/26/2006, 07:44 PM

IS this a new unit?

If it is new, you need to make 15-20 gallons of water and let it run down the drain. The new membranes are protected with an oily coating.

Bean

tony098 · 02/26/2006, 07:51 PM

Thanks Bean.

It is a new unit. I guess I'll need to drain 20 gals.

BeanAnimal · 02/26/2006, 08:30 PM

You should also have a TDS meter. You can't rely on color chaning resin or your eyeballs to tell when or if something is wrong.

Make it a habbit to record

TDS of the tap water
TDS of the RO output
TDS of the DI output (should be 0)

DO this once a month or so. Also keep track of how much water you make and an idea of the average temp of the incoming water. You will get a good idea of how your seystem operates and how often filters need replaced.

When you replace DI resin, you should replace the GAC and other Sediment filters as well. The RO membrane should last several years under normal use.

Bean

PatMayo · 02/27/2006, 12:01 AM

I don't agree with replacing the GAC and other filters when you replace the DI resin. The Di reisn is usually the first to go. I had to replace mine after about 150 gallons. It really depends on the TDS of your incoming water. The Di resin will only take out so many PPM of crap. Once you get to that PPM the di resin will be exhausted. With mine you coud tell by the color of the resin and of course the TDS meter confimed this.

You shoud replace the other filter sans the membrane at least once a year. The membrane under normal use should last about 3 to 5 years. Most people would not be able to afford to use RO/DI if you had to replace all filters everytime you changed the DI resin.

WWW.airwaterice.com can give you more information regarding these issues.

http://static.zoovy.com/merchant/the..._to_change.pdf

I will change my sediment filters when system performance drops off.

Anyway check out the website and you will get the answers you need.

Regards,

Pat

BeanAnimal · 02/27/2006, 12:34 AM

[QUOTE]Originally posted by PatMayo
I don't agree with replacing the GAC and other filters when you replace the DI resin. The Di reisn is usually the first to go. I had to replace mine after about 150 gallons. It really depends on the TDS of your incoming water. The Di resin will only take out so many PPM of crap. Once you get to that PPM the di resin will be exhausted. With mine you coud tell by the color of the resin and of course the TDS meter confimed this.

Don't get in the habbit of relying on the color of the resin... It is more eye candy than a real indication of resin life. A TDS meter is the best way to determine when it is time to change the resin.

You shoud replace the other filter sans the membrane at least once a year.

Yes at least once a year is the minimum.... and I based my comments on the fact that most of use will change resin every 9 -12 months or so.

Now the next qeustion.... you only get 150 Gallons out of your RESIN? What membrane are you using and what is your input TDS. Something does not sound right here.

BeanAnimal · 02/27/2006, 12:35 AM

BTW I own the AWI Typhoon III unit and have been very happy with it.

AZDesertRat · 02/27/2006, 09:45 AM

Prefilters and carbons should be replaced every 6 months religously, regardless of how much water you have produced. Remember you are removing the chlorine disinfectant so there is a slight possibility of bacteria growing anywhere downstream of the carbon. I have seen this happen more than once with poor maintenance. Also make sure you clean and disinfect the housings at least once per yeare if not every filter change.
DI resin is entirely dependent on the quality of your raw water and your membrane. I personally get about 200 gallons per 24 oz refill but my raw water TDS averages over 600. My 75 GPD Dow Filmtec RO membrane gets that down to between 11 and 13.

You cannot put a timeframe on DI replacements such as 6 months or 9 months. Get and use a TDS meter or conductivity meter and forget about color changing resin, it is a very poor indicator of DI condition. After several changes you will get a feel for resin life but still should use the TDS meter at least once a month if not more often.

PatMayo · 02/27/2006, 10:18 AM

AZDesertRat
I agree, hence my use of the TDS meter. It is the best measuring tool. What is acceptable as a high TDS? Of course zero is good, but how high can you go without seriously impacting the quality of the water?

BeanAnimal, I use the TDS meter as well. The memebrane is the 75 GPD unit. I checked my input TDS the other day but I cannot recall what it was. I will recheck it tonight. I changed the resin when the TDS got to 3 or 4 ppm. Can you go higher? I try to keep it at zero always.

tony098,
There you go. All the answers you wanted and more. Great website eh?

Regards,

Pat

BeanAnimal · 02/27/2006, 11:13 AM

Pat I am not sure what is acceptable, I would think that the number has to be whatever your are comfortable with.

I strive for 0 but would not panic if it was 1 or 2. Others may be ok with 10 or 15, or not go above 0.

Your resin usage me be on par if your TDS is as high as AZrats... If it is lower than his, then you may have another problem.

Bean

FuzzyLogic · 02/27/2006, 11:26 AM

Quote:

Originally posted by AZDesertRat
Remember you are removing the chlorine disinfectant so there is a slight possibility of bacteria growing anywhere downstream of the carbon. I have seen this happen more than once with poor maintenance. Also make sure you clean and disinfect the housings at least once per yeare if not every filter change.

How do you disinfect the system? Would this include EVERYTHING downstream from the GAC(membrane housing, DI housing, RO tubing, etc...) or just the GAC housing?

AZDesertRat · 02/27/2006, 12:03 PM

Watts Premier describes the procedure here:

http://www.wattspremier.com/watts/we...ID=27&DID=15#4

I believe you can find it other places also. They don't really give enough detail but you need to either remove the membrane while doing this or at least disconnect the line from your final prefilter or carbon to the membrane and flush at that point. I remove my membrane myself and flush the entire system including all tubing and pressure tanks. Flush it well before reinstalling the membrane because chlorine can damage a TFC membrane.

PatMayo · 02/27/2006, 12:39 PM

Good information to have. I didn't know you needed to flush like that.

Regards,

Pat

AZDesertRat · 02/27/2006, 01:11 PM

Most end users don't know this. And unfortunately a good portion of the vendors either fail to mention it at all or fail to stress the importance of this procedure. I have had Heterotrophic Plate Counts (HPCs), or bacteria counts, performed on RO fiter arrays that had not been serviced and the sheer number of viable bacteria and viruses was amazing. Most of this is between the carbon and the membrane but you can build up a horrible slime layer on the membrane causing biofouling and failure which could in turn cause this stuff to pass into the product water stream if it ruptures or fails. Not a pretty sight.
Everyone should be performing this on an annual basis and especially if you use your unit for drinking water, have clear housings exposed to a light source or heat or use it very infrequently.

tony098 · 02/27/2006, 03:18 PM

I just tested my water

Tap water: 350 ppm
RO: 38
DI: 1

Is the RO good enough for drinking?

BeanAnimal · 02/27/2006, 03:22 PM

Well it is sure better than 350, what you would be drinking without the filter :0

aquaman67 · 02/27/2006, 04:10 PM

tony098,

Where did you get your RO unit?

tony098 · 02/27/2006, 04:52 PM

aquaman67 - airwaterice.com, I get the dual home reef unit.

02/26/2006, 07:36 PM	#1
tony098 Registered Member Join Date: Apr 2004 Posts: 161	RO/DI water quality How can I check the quality of my RO unit's output? When I pour the water from the storage tank, the water has lots of microbubble and oily surface; this goes away if I let the water sits for couple minutes. Is this normal?

02/27/2006, 12:01 AM	#6
PatMayo Registered Member Join Date: Sep 2005 Location: Seattle Posts: 2,843	I don't agree with replacing the GAC and other filters when you replace the DI resin. The Di reisn is usually the first to go. I had to replace mine after about 150 gallons. It really depends on the TDS of your incoming water. The Di resin will only take out so many PPM of crap. Once you get to that PPM the di resin will be exhausted. With mine you coud tell by the color of the resin and of course the TDS meter confimed this. You shoud replace the other filter sans the membrane at least once a year. The membrane under normal use should last about 3 to 5 years. Most people would not be able to afford to use RO/DI if you had to replace all filters everytime you changed the DI resin. WWW.airwaterice.com can give you more information regarding these issues. http://static.zoovy.com/merchant/the..._to_change.pdf I will change my sediment filters when system performance drops off. Anyway check out the website and you will get the answers you need. Regards, Pat __________________ 90 AGA Megaflow (Setup 1-24-06) 120 Lbs. Liverock EuroReef RS 100 Skimmer 2 X 150 MH 2 X 96 watt PC Actinic 2 Clarki Clowns (31 months old) 1 Niger Trigger (Owned 6 months) 2 Tunze 6055 PH Current Tank Info: 90 AGA Megaflow To Be Mixed Reef

02/27/2006, 10:18 AM	#10
PatMayo Registered Member Join Date: Sep 2005 Location: Seattle Posts: 2,843	AZDesertRat I agree, hence my use of the TDS meter. It is the best measuring tool. What is acceptable as a high TDS? Of course zero is good, but how high can you go without seriously impacting the quality of the water? BeanAnimal, I use the TDS meter as well. The memebrane is the 75 GPD unit. I checked my input TDS the other day but I cannot recall what it was. I will recheck it tonight. I changed the resin when the TDS got to 3 or 4 ppm. Can you go higher? I try to keep it at zero always. tony098, There you go. All the answers you wanted and more. Great website eh? Regards, Pat __________________ 90 AGA Megaflow (Setup 1-24-06) 120 Lbs. Liverock EuroReef RS 100 Skimmer 2 X 150 MH 2 X 96 watt PC Actinic 2 Clarki Clowns (31 months old) 1 Niger Trigger (Owned 6 months) 2 Tunze 6055 PH Current Tank Info: 90 AGA Megaflow To Be Mixed Reef

02/27/2006, 12:39 PM	#14
PatMayo Registered Member Join Date: Sep 2005 Location: Seattle Posts: 2,843	Good information to have. I didn't know you needed to flush like that. Regards, Pat __________________ 90 AGA Megaflow (Setup 1-24-06) 120 Lbs. Liverock EuroReef RS 100 Skimmer 2 X 150 MH 2 X 96 watt PC Actinic 2 Clarki Clowns (31 months old) 1 Niger Trigger (Owned 6 months) 2 Tunze 6055 PH Current Tank Info: 90 AGA Megaflow To Be Mixed Reef

02/26/2006, 07:37 PM	#2
TitansFan Registered Member Join Date: Dec 2005 Location: Spring Hill, TN Posts: 1,364	get a TDS meter.

02/26/2006, 07:44 PM	#3
BeanAnimal Registered Member Join Date: Feb 2003 Location: Pittsburgh Posts: 20,772	IS this a new unit? If it is new, you need to make 15-20 gallons of water and let it run down the drain. The new membranes are protected with an oily coating. Bean

02/26/2006, 07:51 PM	#4
tony098 Registered Member Join Date: Apr 2004 Posts: 161	Thanks Bean. It is a new unit. I guess I'll need to drain 20 gals.

02/26/2006, 08:30 PM	#5
BeanAnimal Registered Member Join Date: Feb 2003 Location: Pittsburgh Posts: 20,772	You should also have a TDS meter. You can't rely on color chaning resin or your eyeballs to tell when or if something is wrong. Make it a habbit to record TDS of the tap water TDS of the RO output TDS of the DI output (should be 0) DO this once a month or so. Also keep track of how much water you make and an idea of the average temp of the incoming water. You will get a good idea of how your seystem operates and how often filters need replaced. When you replace DI resin, you should replace the GAC and other Sediment filters as well. The RO membrane should last several years under normal use. Bean

02/27/2006, 12:34 AM	#7
BeanAnimal Registered Member Join Date: Feb 2003 Location: Pittsburgh Posts: 20,772	[QUOTE]Originally posted by PatMayo I don't agree with replacing the GAC and other filters when you replace the DI resin. The Di reisn is usually the first to go. I had to replace mine after about 150 gallons. It really depends on the TDS of your incoming water. The Di resin will only take out so many PPM of crap. Once you get to that PPM the di resin will be exhausted. With mine you coud tell by the color of the resin and of course the TDS meter confimed this. Don't get in the habbit of relying on the color of the resin... It is more eye candy than a real indication of resin life. A TDS meter is the best way to determine when it is time to change the resin. You shoud replace the other filter sans the membrane at least once a year. Yes at least once a year is the minimum.... and I based my comments on the fact that most of use will change resin every 9 -12 months or so. Now the next qeustion.... you only get 150 Gallons out of your RESIN? What membrane are you using and what is your input TDS. Something does not sound right here.

02/27/2006, 12:35 AM	#8
BeanAnimal Registered Member Join Date: Feb 2003 Location: Pittsburgh Posts: 20,772	BTW I own the AWI Typhoon III unit and have been very happy with it.

02/27/2006, 09:45 AM	#9
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	Prefilters and carbons should be replaced every 6 months religously, regardless of how much water you have produced. Remember you are removing the chlorine disinfectant so there is a slight possibility of bacteria growing anywhere downstream of the carbon. I have seen this happen more than once with poor maintenance. Also make sure you clean and disinfect the housings at least once per yeare if not every filter change. DI resin is entirely dependent on the quality of your raw water and your membrane. I personally get about 200 gallons per 24 oz refill but my raw water TDS averages over 600. My 75 GPD Dow Filmtec RO membrane gets that down to between 11 and 13. You cannot put a timeframe on DI replacements such as 6 months or 9 months. Get and use a TDS meter or conductivity meter and forget about color changing resin, it is a very poor indicator of DI condition. After several changes you will get a feel for resin life but still should use the TDS meter at least once a month if not more often.

02/27/2006, 11:13 AM	#11
BeanAnimal Registered Member Join Date: Feb 2003 Location: Pittsburgh Posts: 20,772	Pat I am not sure what is acceptable, I would think that the number has to be whatever your are comfortable with. I strive for 0 but would not panic if it was 1 or 2. Others may be ok with 10 or 15, or not go above 0. Your resin usage me be on par if your TDS is as high as AZrats... If it is lower than his, then you may have another problem. Bean

02/27/2006, 12:03 PM	#13
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	Watts Premier describes the procedure here: http://www.wattspremier.com/watts/we...ID=27&DID=15#4 I believe you can find it other places also. They don't really give enough detail but you need to either remove the membrane while doing this or at least disconnect the line from your final prefilter or carbon to the membrane and flush at that point. I remove my membrane myself and flush the entire system including all tubing and pressure tanks. Flush it well before reinstalling the membrane because chlorine can damage a TFC membrane.

02/27/2006, 01:11 PM	#15
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	Most end users don't know this. And unfortunately a good portion of the vendors either fail to mention it at all or fail to stress the importance of this procedure. I have had Heterotrophic Plate Counts (HPCs), or bacteria counts, performed on RO fiter arrays that had not been serviced and the sheer number of viable bacteria and viruses was amazing. Most of this is between the carbon and the membrane but you can build up a horrible slime layer on the membrane causing biofouling and failure which could in turn cause this stuff to pass into the product water stream if it ruptures or fails. Not a pretty sight. Everyone should be performing this on an annual basis and especially if you use your unit for drinking water, have clear housings exposed to a light source or heat or use it very infrequently.

02/27/2006, 03:18 PM	#16
tony098 Registered Member Join Date: Apr 2004 Posts: 161	I just tested my water Tap water: 350 ppm RO: 38 DI: 1 Is the RO good enough for drinking?

02/27/2006, 03:22 PM	#17
BeanAnimal Registered Member Join Date: Feb 2003 Location: Pittsburgh Posts: 20,772	Well it is sure better than 350, what you would be drinking without the filter :0

02/27/2006, 04:10 PM	#18
aquaman67 Registered Member Join Date: Feb 2002 Location: Tennessee Posts: 7,629	tony098, Where did you get your RO unit?

02/27/2006, 04:52 PM	#19
tony098 Registered Member Join Date: Apr 2004 Posts: 161	aquaman67 - airwaterice.com, I get the dual home reef unit.