ro/di sytem ?

drillsar · 08/29/2006, 11:38 PM

I have a watergeneral and I was told to get the 75gpd Dow membrane my TDS is showin about 6.

Is it worth to replace all the filters or should I get a typhoon III?

the membrane makes the ro/di system correct?

kraze3 · 08/30/2006, 12:08 AM

The 75gpd membranes are better than the 100gpd ones. They have a higher rejection rate. I have no experience with water general. How old is the unit? I would think that if you replace the membranes then it should be back down to 0 TDS. After a while all membranes need to be replaced.

On another note I have a typhoon III and I highly recommend it. Ive never had a problem with it.

sammyp · 08/30/2006, 12:14 AM

where did you get your typhoon III ?

drillsar · 08/30/2006, 12:23 AM

I wished I known to get the 75gpd when I bought it.

mission man · 08/30/2006, 12:37 AM

airwaterice.com has the typhoon III. I got one a few months back, works great.

smleee · 08/30/2006, 10:10 AM

Quote:

Originally posted by drillsar
I have a watergeneral and I was told to get the 75gpd Dow membrane my TDS is showin about 6.

Is it worth to replace all the filters or should I get a typhoon III?

the membrane makes the ro/di system correct?

Post a link to the WG? I'm not certain of the configuration, how many stages, etc. Also, is 6ppm your RO/DI reading or RO only reading? Please post the input TDS, RO only TDS, and RO/DI TDS and we can better help you decide what filters to get, etc. Also your prefilters should be replaced every 6 months regardless of usage.

eee

drillsar · 08/30/2006, 01:43 PM

www.watergeneral.com RD-102, Im thinking just replacing all the filters on this.

RO/DI reads 6 , RO only 12

getting a 75gpd Dow membrane instead.

raaden · 08/30/2006, 01:57 PM

I think your issue is with the DI not the RO. Make sure you have good flow through your DI and there is no channeling. Lower Quality DI will not let the water flow through correctly and will not give 0TDS.

What is your starting TDS that will tell alot

drillsar · 08/30/2006, 02:08 PM

what you mean starting TDS?

smleee · 08/30/2006, 03:34 PM

Quote:

Originally posted by drillsar
what you mean starting TDS?

Input water (as I asked before). The water you are feeding the unit. There is something wrong with the DI if you are getting 6ppm output.

EDIT after looking at link: The dual hollow horizontal DI tube setup is an inefficient design that is flawed. You may try a couple things first - mount the DI vertically (for bottom up flow). Pack as much resin in there as you can. See what that gives you. You are most likely experiencing channeling and/or your DI is exhausted. This is still not as effective as a full size vertical DI canister that holds 24oz resin cartridges with bottom up flow path.

eee

smleee · 08/30/2006, 03:45 PM

Quote:

Originally posted by drillsar
getting a 75gpd Dow membrane instead. [/B]

Yes, if you do need a membrane (we'll know after you post your input TDS) make sure and get a genuine Dow FilmTec membrane, there are knock-offs out there along with membranes that just "use" the Dow material - both not the same.

eee

HighlandReef · 08/30/2006, 08:43 PM

i just ordered the typhoon, have heard alot of good about them!

drillsar · 08/30/2006, 09:13 PM

Tap water is 178 on tds is that what you mean starting?

raaden · 08/31/2006, 05:48 AM

That is a pretty hefty starting TDS. I think the membrane is doing a pretty good job getting that down to 12. Your issue is exactly what smlee is describing. No DI that is mounted horizontally will do any better than cutting the ro result in half. Channeling is definitely your problem after hearing this. Another long term issue is that you will completely use up the bottom half of the resin before the top is even starting to fade, so you will be wasting half of your resin as well. There is not much you can do with that DI chamber you have other than to try to remount it vertically.

The typhoon (do you mean Typhoon III) is a great system and is what I have as well. It has been great and I wouldn't trade it for anything else out there.

raaden · 08/31/2006, 05:52 AM

One other thing, if you can't or don't want to mount your existing DI vertically you can get a good one here for not alot of money. I would probably go with the external one as this is completely refillable and will last alot longer than the smaller one that is on there now.

AZDesertRat · 08/31/2006, 08:33 AM

Your membrane is not doing a very good job. My tap water TDS is 736 and my RO only gets that to 7.7 . If its less than 96% or so it eats you up in DI filtersand with the original DI design you will never see a TDS of 0 I don't care what you do or how you mount it. Take raadens advice and get the better add on DI and some time soon replace the membrane with a 75 GPD Dow Filmtec.

smleee · 08/31/2006, 09:51 AM

Quote:

Originally posted by drillsar
Tap water is 178 on tds is that what you mean starting?

Yes, with 178ppm input and 12ppm output on the RO that means your membrane is at ~93% rejection. Probably not "bad" for that membrane as it is not a Dow FilmTec, but nonetheless, it is not good. Dow's are rated at 98% @ 50psi. Mine is currently producing over 99% rejection at 55psi (I see AZDesertRat is at ~99% also, though I'm sure his meters are far more accurate than mine); of course YMMV depending on "what" is actually in the water, but you get what I'm saying.

That DI needs to be modified or changed to a full size vertical canister - I'd go with the 2nd, it will give you more favorable results and for longer.

eee

raaden · 08/31/2006, 10:19 AM

Wait a sec... there are a couple of things going on here that I think are being missed when you compare those numbers, and I am only posting this as informational not to start a war. They are not really needed to fix drillsar's problem but are good to know anyway, and I have not seen them posted elsewhere. Please feel free to correct me on any of these, but the bottom line is your DI is not cutting it.

1. I am pretty sure that the membrane he has is not a 98% membrane. My guess would be that it is 92% Dow Mat membrane at best. Remember there are many different RO membrane options. The 100GPD DOW Filmtec membrane is only 88% I think and that is a true Dow membrane you can choose as an option from both AWI and purleH2O.

2. The "what" that is in the water makes a huge difference. There are alot of things that go through the RO because the particles are too small to be caught. The 98% is based on known samples with all particles able to be filtered and not based on what you should expect to see coming from your water company. Some particles are just too small to be caught by any RO, I believe the most common of these is Chloramine, and other additives that the water company would be introducing into the water for its own purposes. This is the whole reason that there is a DI in the first place. All of these things are measurable as TDS but the RO will only even attempt to remove 'most' of them. This is why if you get a larger system for a whole house they want you to send them a sample of your feedwater so that they can design a better system than the off the shelf'ers

Anyway hope this is helpful.

smleee · 08/31/2006, 10:48 AM

We know from the original 6ppm after DI that he had a problem with the DI - as it should be 0ppm in any case. But we also need to know the input TDS. Say he had 50ppm input? Then getting an RO of 12 would be terrible and we could try to address that too.

Yes, I believe the 100GPD Dow is a 90% membrane. The 75GPD Dow is a 98% @50psi membrane. I can't recall a member who was not getting close to 98% (with 75GPD Dow) when new, but I'm sure it happens, hence "YMMV".

drillsar · 08/31/2006, 02:03 PM

Ok i did another test at my friends house starting tds 215 with RO 24 Wth DI 4. So what is it?

So im guessing my membrane is taking 90% down to 24 and my DI is taking another 90% now Im guessing here but if I got a 75gpd Dow membrane my RO would be like 3 and DI would go to 0 right?

raaden · 08/31/2006, 02:11 PM

You did the test with his water right.

If that is the case you got pretty close to the same results and my guess is that the DI got sloshed around a bit so it is working a little bit better 24--> 4. If you have the money I would get a new vertical DI and replace the membrane with a DOW FilmTec 75 GPD 98%. If you can only do one get the DI.

08/29/2006, 11:38 PM	#1
drillsar Registered Member Join Date: Apr 2003 Location: West Orange, NJ Posts: 2,838	ro/di sytem ? I have a watergeneral and I was told to get the 75gpd Dow membrane my TDS is showin about 6. Is it worth to replace all the filters or should I get a typhoon III? the membrane makes the ro/di system correct?

08/30/2006, 12:14 AM	#3
sammyp Registered Member Join Date: Aug 2006 Location: Long Guy Land, NY Posts: 81	where did you get your typhoon III ? __________________ There he goes. Too weird to live, and too rare to die. Just another freak, in the freak kingdom. Humans are just smart monkeys. If you think about it, the earth is just a big piece of live rock. Current Tank Info: 10 gallon AGA

08/30/2006, 12:08 AM	#2
kraze3 Registered Member Join Date: Jan 2006 Location: RI Posts: 2,373	The 75gpd membranes are better than the 100gpd ones. They have a higher rejection rate. I have no experience with water general. How old is the unit? I would think that if you replace the membranes then it should be back down to 0 TDS. After a while all membranes need to be replaced. On another note I have a typhoon III and I highly recommend it. Ive never had a problem with it.

08/30/2006, 12:23 AM	#4
drillsar Registered Member Join Date: Apr 2003 Location: West Orange, NJ Posts: 2,838	I wished I known to get the 75gpd when I bought it.

08/30/2006, 12:37 AM	#5
mission man Registered Member Join Date: Jan 2006 Location: Michigan Posts: 216	airwaterice.com has the typhoon III. I got one a few months back, works great.

08/30/2006, 01:43 PM	#7
drillsar Registered Member Join Date: Apr 2003 Location: West Orange, NJ Posts: 2,838	www.watergeneral.com RD-102, Im thinking just replacing all the filters on this. RO/DI reads 6 , RO only 12 getting a 75gpd Dow membrane instead.

08/30/2006, 01:57 PM	#8
raaden Registered Member. Join Date: Jun 2004 Location: Raleigh NC Posts: 505	I think your issue is with the DI not the RO. Make sure you have good flow through your DI and there is no channeling. Lower Quality DI will not let the water flow through correctly and will not give 0TDS. What is your starting TDS that will tell alot

08/30/2006, 02:08 PM	#9
drillsar Registered Member Join Date: Apr 2003 Location: West Orange, NJ Posts: 2,838	what you mean starting TDS?

08/30/2006, 08:43 PM	#12
HighlandReef Chalice Monger Join Date: Jul 2006 Location: NW Indiana Posts: 1,163	i just ordered the typhoon, have heard alot of good about them!

08/30/2006, 09:13 PM	#13
drillsar Registered Member Join Date: Apr 2003 Location: West Orange, NJ Posts: 2,838	Tap water is 178 on tds is that what you mean starting?

08/31/2006, 05:48 AM	#14
raaden Registered Member. Join Date: Jun 2004 Location: Raleigh NC Posts: 505	That is a pretty hefty starting TDS. I think the membrane is doing a pretty good job getting that down to 12. Your issue is exactly what smlee is describing. No DI that is mounted horizontally will do any better than cutting the ro result in half. Channeling is definitely your problem after hearing this. Another long term issue is that you will completely use up the bottom half of the resin before the top is even starting to fade, so you will be wasting half of your resin as well. There is not much you can do with that DI chamber you have other than to try to remount it vertically. The typhoon (do you mean Typhoon III) is a great system and is what I have as well. It has been great and I wouldn't trade it for anything else out there.

08/31/2006, 05:52 AM	#15
raaden Registered Member. Join Date: Jun 2004 Location: Raleigh NC Posts: 505	One other thing, if you can't or don't want to mount your existing DI vertically you can get a good one here for not alot of money. I would probably go with the external one as this is completely refillable and will last alot longer than the smaller one that is on there now.

08/31/2006, 08:33 AM	#16
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	Your membrane is not doing a very good job. My tap water TDS is 736 and my RO only gets that to 7.7 . If its less than 96% or so it eats you up in DI filtersand with the original DI design you will never see a TDS of 0 I don't care what you do or how you mount it. Take raadens advice and get the better add on DI and some time soon replace the membrane with a 75 GPD Dow Filmtec.

08/31/2006, 10:19 AM	#18
raaden Registered Member. Join Date: Jun 2004 Location: Raleigh NC Posts: 505	Wait a sec... there are a couple of things going on here that I think are being missed when you compare those numbers, and I am only posting this as informational not to start a war. They are not really needed to fix drillsar's problem but are good to know anyway, and I have not seen them posted elsewhere. Please feel free to correct me on any of these, but the bottom line is your DI is not cutting it. 1. I am pretty sure that the membrane he has is not a 98% membrane. My guess would be that it is 92% Dow Mat membrane at best. Remember there are many different RO membrane options. The 100GPD DOW Filmtec membrane is only 88% I think and that is a true Dow membrane you can choose as an option from both AWI and purleH2O. 2. The "what" that is in the water makes a huge difference. There are alot of things that go through the RO because the particles are too small to be caught. The 98% is based on known samples with all particles able to be filtered and not based on what you should expect to see coming from your water company. Some particles are just too small to be caught by any RO, I believe the most common of these is Chloramine, and other additives that the water company would be introducing into the water for its own purposes. This is the whole reason that there is a DI in the first place. All of these things are measurable as TDS but the RO will only even attempt to remove 'most' of them. This is why if you get a larger system for a whole house they want you to send them a sample of your feedwater so that they can design a better system than the off the shelf'ers Anyway hope this is helpful.

08/31/2006, 10:48 AM	#19
smleee Registered Member Join Date: May 2004 Location: Boise, ID Posts: 1,344	We know from the original 6ppm after DI that he had a problem with the DI - as it should be 0ppm in any case. But we also need to know the input TDS. Say he had 50ppm input? Then getting an RO of 12 would be terrible and we could try to address that too. Yes, I believe the 100GPD Dow is a 90% membrane. The 75GPD Dow is a 98% @50psi membrane. I can't recall a member who was not getting close to 98% (with 75GPD Dow) when new, but I'm sure it happens, hence "YMMV".

08/31/2006, 02:03 PM	#20
drillsar Registered Member Join Date: Apr 2003 Location: West Orange, NJ Posts: 2,838	Ok i did another test at my friends house starting tds 215 with RO 24 Wth DI 4. So what is it? So im guessing my membrane is taking 90% down to 24 and my DI is taking another 90% now Im guessing here but if I got a 75gpd Dow membrane my RO would be like 3 and DI would go to 0 right?

08/31/2006, 02:11 PM	#21
raaden Registered Member. Join Date: Jun 2004 Location: Raleigh NC Posts: 505	You did the test with his water right. If that is the case you got pretty close to the same results and my guess is that the DI got sloshed around a bit so it is working a little bit better 24--> 4. If you have the money I would get a new vertical DI and replace the membrane with a DOW FilmTec 75 GPD 98%. If you can only do one get the DI.