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RO/DI
- Thread starter jasonrog
- Start date
Newts":uiq6oqca said:Does anyone know were the RO membranes are made?(Spectrapure and Kent don't actually produce thier own membranes)I remember hearing one time that DuPont pretty mutch produces all membranes.I think they were the inventers of this product.All these companies just build the unit that house the filters.That would mean that all RO membranes are equal.I'm not absolutly sure of this so if anyone knows for sure please correct me.
DOW makes most of the membranes in this country. I've seen both Spectrapure and Kent units ship with DOW Filmtec's. Spectrapure claims they test each membrane and rate them for a given output, while most other companies just take DOW's word for it.
The idea that one unit is better than another is malarky. 0-1 PPM TDS is 0-1 PPM TDS. All the components come from precious few manufacturers. It is quite easy to screw it up, I've seen some idiotic stores sell people 100% cation or anion resins as their ONLY DI and thus really screw the water up, but as long as someone who knows what they are doing builds the unit (and they aren't under indictment or in rehab :wink: ) then you can get excellent water relatively easily. IMO Aquatic Reef Systems makes the best bang for the buck systems out there. Kent's are okay but too pricey for what you get, even at wholetail prices.
Stage One: Sediment Filter, 5-Micron Spun Poly Cartridge.
Stage Two: Taste and Odor Filter, Pre-Carbon.
Stage Three: Sediment Filter, 1 Micron Spun Poly Cartridge.
Stage Four: Reverse Osmosis Membrane.
Stage Five: Post-Filter, In-Line Granular Activated Carbon
Stage Two: Taste and Odor Filter, Pre-Carbon.
Stage Three: Sediment Filter, 1 Micron Spun Poly Cartridge.
Stage Four: Reverse Osmosis Membrane.
Stage Five: Post-Filter, In-Line Granular Activated Carbon
hi.
Obviously, not all "five" stages are created equal. The second stage is confusing me... what the heck it it?
I would put stage three on stage two, and put a REAL carbon filter in its place. The stage five is misleading because it is useful for drinking water purpose (you want to filter the water from the bladder tank before drinking it just in case), but useless for aquarium.
So it would be:
Stage One: Sediment Filter, 5-Micron Spun Poly Cartridge.
Stage Two: Sediment Filter, 1 Micron Spun Poly Cartridge.
Stage Three: Carbon block filter, 1 Micron
Stage Four: Reverse Osmosis Membrane.
So it is a 4 stage RO, with the fifth filter for drinking, and the user can get an add-on DI if they desire a DI stage.
An alternative is the following:
Stage One: Sediment Filter, 5-Micron Spun Poly Cartridge.
Stage Two: Carbon block filter, 1 Micron
Stage Three: Reverse Osmosis Membrane.
Stage Four: DI cartidge.
Obviously, not all "five" stages are created equal. The second stage is confusing me... what the heck it it?
I would put stage three on stage two, and put a REAL carbon filter in its place. The stage five is misleading because it is useful for drinking water purpose (you want to filter the water from the bladder tank before drinking it just in case), but useless for aquarium.
So it would be:
Stage One: Sediment Filter, 5-Micron Spun Poly Cartridge.
Stage Two: Sediment Filter, 1 Micron Spun Poly Cartridge.
Stage Three: Carbon block filter, 1 Micron
Stage Four: Reverse Osmosis Membrane.
So it is a 4 stage RO, with the fifth filter for drinking, and the user can get an add-on DI if they desire a DI stage.
An alternative is the following:
Stage One: Sediment Filter, 5-Micron Spun Poly Cartridge.
Stage Two: Carbon block filter, 1 Micron
Stage Three: Reverse Osmosis Membrane.
Stage Four: DI cartidge.
I was debating between a SpectraPure or an ARS. I did not like the price aspect of Spectrapure nor their customor service.
I finally said the GOAL of any RO/DI unit is 0 TDS measured in uS's and not ppm's. I got an ARS and with it ZERO uS's and saved much $$'s.
Many differnet brands will attain this goal.
Regards,
Brad
I finally said the GOAL of any RO/DI unit is 0 TDS measured in uS's and not ppm's. I got an ARS and with it ZERO uS's and saved much $$'s.
Many differnet brands will attain this goal.
Regards,
Brad
hi.
I can drive my car for 30 miles after the gauage say it is empty! This is how I save money on gasoline! :wink:
Seriously, if you TDS meter reads "0", it just means that conductivity measurement is out of the range. Regular DI resin used in both reef hobby and semiconductor industry can not achieve 0 uS/cm conductivity.
I can drive my car for 30 miles after the gauage say it is empty! This is how I save money on gasoline! :wink:
Seriously, if you TDS meter reads "0", it just means that conductivity measurement is out of the range. Regular DI resin used in both reef hobby and semiconductor industry can not achieve 0 uS/cm conductivity.
Craig, I thought that I had the absolute worst quality of tapwater in the world down here, however it looks as though yours is even worse. Gotta love those Texas water purity laws. My water also contains tons of calcium carbonate and I have had to install water softeners to my incoming water mains to prevent the CaCO3 from precipitating on the membranes and thus clogging them up.
I would like to add my opinion to the argument as to which RO unit is better. I have three units, a Kent unit in my office (4 part), a spectrapure unit feeding my ice machine (4 part unit with DI stage removed - previously used on my tank and removed for reasons to be stated later) and a 4 part Aquatic Reef Systems unit feeding the topoff tank for my home aquarium. I do agree that Spectrapure offers excellent customer service (and I have extensive experience with that), and the overall quality of their unit is good, however I am a little peeved with them. All of my units contain 100 gpd membranes. All are fed by softened, 60 psi, 75 degree water (close the parameters under which the membranes are rated). All post-membrane water comes out at about 50 ppm's. Where my beef with Spectrapure lies is the fact that I am getting between 50 and 70 gpd from the Kent and ARS units, however have never gotten more than 20 gpd from the Spectrapure membranes rated at 80 or 100 gpd. I have discussed this with Spectrapure, and have replace the membrane 2 or 3 times, have adjusted the waste water flow restrictor and have done just about everything else under the sun, however the membrane which Spectapure sells just is not putting out as much water as the others. As I said, they all put out the same TDS's. My statement to Jason would be: If your incoming water is already good (<100 ppm's) and the membrane is giving you less than 5 ppm's alone, then I do not think that you need a DI stage. (Arguing about 0 ppm's vs 1 ppm vs 5 ppm's is completely pointless as far as I am concerned. As soon as you put that ultrapure, 0 ppm water into a holding tank, it will immediately pick up lots of "ppm's" from the air anyway since water that pure will have an amazing affinity for any type of ions in its viscinity - so will the water in your tank unless the tank is inside a purified air environment.)
I would like to add my opinion to the argument as to which RO unit is better. I have three units, a Kent unit in my office (4 part), a spectrapure unit feeding my ice machine (4 part unit with DI stage removed - previously used on my tank and removed for reasons to be stated later) and a 4 part Aquatic Reef Systems unit feeding the topoff tank for my home aquarium. I do agree that Spectrapure offers excellent customer service (and I have extensive experience with that), and the overall quality of their unit is good, however I am a little peeved with them. All of my units contain 100 gpd membranes. All are fed by softened, 60 psi, 75 degree water (close the parameters under which the membranes are rated). All post-membrane water comes out at about 50 ppm's. Where my beef with Spectrapure lies is the fact that I am getting between 50 and 70 gpd from the Kent and ARS units, however have never gotten more than 20 gpd from the Spectrapure membranes rated at 80 or 100 gpd. I have discussed this with Spectrapure, and have replace the membrane 2 or 3 times, have adjusted the waste water flow restrictor and have done just about everything else under the sun, however the membrane which Spectapure sells just is not putting out as much water as the others. As I said, they all put out the same TDS's. My statement to Jason would be: If your incoming water is already good (<100 ppm's) and the membrane is giving you less than 5 ppm's alone, then I do not think that you need a DI stage. (Arguing about 0 ppm's vs 1 ppm vs 5 ppm's is completely pointless as far as I am concerned. As soon as you put that ultrapure, 0 ppm water into a holding tank, it will immediately pick up lots of "ppm's" from the air anyway since water that pure will have an amazing affinity for any type of ions in its viscinity - so will the water in your tank unless the tank is inside a purified air environment.)
O P Ing":9bz9apx9 said:hi.
I can drive my car for 30 miles after the gauage say it is empty! This is how I save money on gasoline! :wink:
Seriously, if you TDS meter reads "0", it just means that conductivity measurement is out of the range. Regular DI resin used in both reef hobby and semiconductor industry can not achieve 0 uS/cm conductivity.
I have no idea what you are talking about. I do achieve a 0 uS/cm.
hi.I have no idea what you are talking about. I do achieve a 0 uS/cm.
Sorry about that. Most DI resins are rated for 18-20 megaOhm, or in conductivity unit, 0.05 uS. Common conductivity meter does not have the correct range and precision, so it just give you a "0" reading. Keep in mind that this is a ultrapure water already, but incorrect to state that anyone "achieves" a 0 uS/cm. Some of you already know that I like to pick on little, minor, minute, insignificant points like this :wink:
texman":7y4g6ond said:Craig, I thought that I had the absolute worst quality of tapwater in the world down here, however it looks as though yours is even worse. Gotta love those Texas water purity laws.
I lived in Greenville, TX for a short time several years ago. The local's assessment of the tap water was:
"You can take the water out of the swamp, but you can't take the swamp out of the water."
O P Ing":1n1nq610 said:hi.I have no idea what you are talking about. I do achieve a 0 uS/cm.
Sorry about that. Most DI resins are rated for 18-20 megaOhm, or in conductivity unit, 0.05 uS. Common conductivity meter does not have the correct range and precision, so it just give you a "0" reading. Keep in mind that this is a ultrapure water already, but incorrect to state that anyone "achieves" a 0 uS/cm. Some of you already know that I like to pick on little, minor, minute, insignificant points like this :wink:
I am not incorrect in saying I acheive a 0 uS/cm. This what my meter says. Now it may actually be .4 or .3, etc but the meter reads increments of 1. The same can be said of people saying they have a TDS reading of 0 ppm but I hear no one giving them a hard time. We are splitting hairs here.
Some of you already know that I like to pick on little, minor, minute, insignificant points like this
We are splitting hairs here.
May I put you among the rank of P O Johnny and many others. :wink:
I hope that you can understand that I have background in chemical education, and often get a bit too avid to voice my opinion when people states that they have 0 measurement. Conversely, I also get a little bit uneasy when my students put down a full 12 digit number for pH calculation.
hi.
On principle, it does not cost anymore to make conductivity meter for different range. For example, it cost the same for meter that measure conductivity between 0.10S/cm to 1.99S/cm and 0.10mS/cm to 1.99mS/cm. But the price for a meter that have finer resolution and precision entail better electronic, thereby more expensive.
Be aware that range, resolution, precision and accuracy are different animals.
On principle, it does not cost anymore to make conductivity meter for different range. For example, it cost the same for meter that measure conductivity between 0.10S/cm to 1.99S/cm and 0.10mS/cm to 1.99mS/cm. But the price for a meter that have finer resolution and precision entail better electronic, thereby more expensive.
Be aware that range, resolution, precision and accuracy are different animals.
hi.
There are two way to get measurement of ultrapure water. One way is what you thinking of. Using a higher resolution (absolute resolution) conductivity meter. Then the answer is, yes, it will cost more if you want it to be able to measure 10pS all the way up to 1mS in 10pS resolution. In fact, I don't know any meter that can do that without changing the range. Another way is to get a meter that specifically designed for ultrapure water. Meter available that can go from 10pS to 1.99uS in 10 pS resolution (relative resolution is about the same as the meter that most of us use) for about the same price as a hobby meter used in hydroponics and reefs.
There are two way to get measurement of ultrapure water. One way is what you thinking of. Using a higher resolution (absolute resolution) conductivity meter. Then the answer is, yes, it will cost more if you want it to be able to measure 10pS all the way up to 1mS in 10pS resolution. In fact, I don't know any meter that can do that without changing the range. Another way is to get a meter that specifically designed for ultrapure water. Meter available that can go from 10pS to 1.99uS in 10 pS resolution (relative resolution is about the same as the meter that most of us use) for about the same price as a hobby meter used in hydroponics and reefs.
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