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The article discusses and compares various brands and models of reverse osmosis membranes, their differences, and their advantages. Answers to the most frequently asked questions are provided.
In one of the previous articles, it was shown that reverse osmosis filters have the most advanced degree of purification. They filter water slowly, but they retain not only common contaminants but also impurities and toxins dissolved in water. Moreover, the reverse osmosis filter membrane traps most biological contaminants such as cholera bacteria, hepatitis viruses, and the Sars-Cov-2 coronavirus. At the outlet of the reverse osmosis filter, we get the purest water without extraneous odors and tastes. Water becomes better for your health, and has an exceptional taste, transparency, and softness.
Other articles considered reverse osmosis filters, which have the most perfect degree of purification, and flow-through microfiltration and ultrafiltration systems – simpler, but quite effective.
Currently, a variety of reverse osmosis systems for home and office use are produced in the world. They differ not only in the brand of the manufacturer but also in the characteristics, as well as features of the device. The most popular are classic RO systems with 4-5 purification stages and replaceable 10-inch drop-in filters. Despite the fact that replaceable membrane elements for them are usually compatible, there are some features. Therefore, we will try to compare different types of these filters and find out how to choose the most suitable reverse osmosis membrane element (module) for each case.
Sizes (dimensions) of reverse osmosis membranes and their marking.
As a rule, the membrane model has a digital marking of the form AABB-CC. Also, the marking may contain additional letters and numbers before and/or after the standard numerical designation, with which different manufacturers indicate different features of the product.
The numbers have the following meaning.
The first two digits of AA are the element diameter in inches multiplied by 10.
Second two digits BB – membrane element length in inches.
The third pair of digits, CC, is the performance of the membrane under laboratory conditions (in gallons per day).
For example, the marking of the most popular American-made membrane Filmtec TW30 1812-50 means:
TW – Tap Water (for tap water);
30 – model number;
18 – element diameter 1.8 inches (44.5 mm);
12 – element length 12 inches (298 mm);
50 – membrane capacity of 50 gallons (about 190 liters) per day.
The “1812” membrane size is the de facto standard for home use. The dimensions of specific elements may vary slightly, as the design of the standard membrane body (vessel) allows for a slight deviation in dimensions.
For reference, approximately:
1 inch = 25.4 mm.
1 gallon = 3.78 liters.
Some popular models of reverse osmosis membranes and their differences.
Filmtec TW30 1812-50
One of the oldest and most popular American-made reverse osmosis membrane models.
Designed for home and office reverse osmosis systems for standard tap water. Has optimal performance. Can operate over a wide pH range. Actual performance is usually higher than stated. Previously produced mainly under the Dow brand. After merging and rebranding, it is increasingly found under the Dupont and Aqualast brands. Both those and other membranes are original, supplied in dry condition, and do not have an expiration date if stored in their original packaging.
The average price is about 40 euros. You can study the characteristics, see other photos and buy them on the ProMarket-EU online store (delivery to all EU countries).
Specifications:
Maximum Operating Pressure: 150 psi (10 bar)
Maximum Operating Temperature: 113F (45C)
Maximum Feed Flow Rate: 7.6 lph
pH Range, Continuous Operation: 2-11*
Maximum Feed Silt Density Index (SDI): 5
Free Chlorine Tolerance: < 0.1 ppm**
Rejection Rate: 98%.
Filmtec TW30 1812-50HR
A new modification of the well-known Filmtec TW30 1812-50 membrane. It has more stable characteristics and can work in a wider range of pressure and pH. Actual performance is usually higher than stated. Previously produced mainly under the Dow brand. After the merger and rebranding, it is increasingly found under the Dupont and Aqualast brands. Both those and other membranes are original, supplied in dry condition, and do not have an expiration date if stored in their original packaging.
The average price is about 55 euros. You can study the characteristics, see other photos and buy in the ProMarket-EU online store (delivery to all EU countries).
Specifications:
Maximum Operating Pressure: 21 bar
Maximum Operating Temperature: 113F (45C)
Maximum Feed Flow Rate: 7.6 lph
pH Range, Continuous Operation: 1-13*
Maximum Feed Silt Density Index (SDI): 5
Free Chlorine Tolerance: < 0.1 ppm**
Rejection Rate: 99 %.
Filmtec BW60 1812-75
New FILMTEC BW60 membrane series has been designed and manufactured by Dow/Dupont with new construction and new materials to replace the previous TW30-1812-75 GPD and guarantee superior performance stability.
The BW (Brackish water) series is suitable not only for standard tap water but also for water from natural sources – wells and artesian wells (after pre-treatment with prefilters). Allows you to filter not only hard but also slightly brackish (but not from the sea!) water. Delivers the high performance of 75 gallons (approx. 280 liters) per day due to the increased membrane active surface. Therefore, it can be used (in addition to home conditions) for small offices, bars, and cafes.
The average price is about 40 euros. You can study the characteristics, see other photos and buy them in the ProMarket-EU online store (delivery to all EU countries).
Specifications:
Maximum Operating Pressure: 10 bar
Maximum Operating Temperature: 113F (45C)
Maximum Feed Flow Rate: 12 lph
pH Range, Continuous Operation: 1-13*
Maximum Feed Silt Density Index (SDI): 5
Free Chlorine Tolerance: < 0.1 ppm**
Rejection Rate: 99 %.
Aquaphor RO-1812-50 Original Reverse Osmosis Membrane
The reverse osmosis module RO ULP 1812-50 (50 gpd) is original for classic Aquaphor reverse osmosis systems. It has an increased active surface of the membrane, but it is not used to increase productivity, but to be able to work in systems with low pressure. Recommended for reverse osmosis systems such as Atoll 460, Osmo 50 classic, RO-50 with a storage tank but without a booster pump (those that work without electricity).
The average price is about 44 euros. You can study the characteristics, see other photos and buy them in the ProMarket-EU online store (delivery to all EU countries).
They are shipped dry and have no expiration date if stored in their original packaging.
Operating characteristics of the membrane:
Operating pressure: 60 psi
Max. operating pressure: 150 psi (10 bar)
Max. incoming water temperature: 45 ℃
Max. sdi Inlet: 5
The concentration of free chlorine Inlet: <0.1ppm
PH Range Inlet during continuous operation: 3 ~ 10
Inlet PH range during the chemical treatment: 2 ~ 12
Max. pressure drop across the membrane of 10 psi (0.07 Mpa)
Stable filtration rating: 97.5%
Vontron EC1812-50 – Reverse Osmosis Original Membrane for 10 Inch systems Low Water Consuming ECO
The reverse osmosis module EC 1812-50 (50 gpd) is an upgraded replacement (substitute) for the well-known Vontron ULP 1812-50 membrane. The difference between ULP1812-50 and EC1812-50 is the following: EC1812-50 has the same filtration characteristics but uses less water.
A characteristic feature of the new Vontron membranes is that the rubber cuff is located farther from the edge of the filter. Due to the original design, this Vontron membrane has the ability to work in both low pressure and normal pressure systems. Under normal operating conditions, less water is sent to the drain, which is important for the EConomy and ECology (hence the EC prefix).
Recommended for reverse osmosis systems such as Aquaphor RO, Aquaphor Trio +, Atoll 450 – 460 – 560, Depuragua, Geyser, Honeywell, NATURE WATER PROFESSIONALS, and similar.
The average price is about 35 euros. You can study the characteristics, see other photos and buy them in the ProMarket-EU online store (delivery to all EU countries).
They are shipped dry and have no expiration date if stored in their original packaging. Each membrane has a serial number to verify its originality. Made in China.
Operating characteristics of the membrane:
- Operating pressure: 60 psi
- Max. operating pressure: 150 psi (10 bar)
- Max. incoming water temperature: 45 ℃
- Max. sdi Inlet: 5
- The concentration of free chlorine Inlet: <0.1ppm
- PH Range Inlet during continuous operation: 3 ~ 10
- Inlet PH range during the chemical treatment: 2 ~ 12
- Max. pressure drop across the membrane of 10 psi (0.07 Mpa)
- Stable filtration rating: 98%
Ionicore Keypra RO membrane TFC 1812 – 50GPD
The newest model of the membrane module is made from high-quality Chinese-made TFC film under the Ionicore brand. The element is not only NSF/ANSI 58 certified, but also complies with the Italian D.M. 174/2004. For this reason, for this membrane, the percentage of purification for each of the harmful substances is known. Average filtration rating – up to 98%. This is somewhat inferior to the new FilmTec models but sufficient for use in home systems using treated tap water.
The average price is about 20 euros. You can study the characteristics, see other photos and buy them in the ProMarket-EU online store (delivery to all EU countries).
They are shipped dry and have no expiration date if stored in their original packaging.
Answers to frequently asked questions (FAQ).
The osmosis process is based on the ability of water to equalize the level of impurities in solutions separated by a membrane.
Reverse osmosis gives exactly the opposite result. The key element of the reverse osmosis system is a special membrane, the pores of which are so small that they do not let through anything that exceeds the size of a water molecule. In this case, the membrane is not used to equalize the density of the liquid, but in order to collect pure water on one side of it, and on the other, a solution that is as saturated as possible with impurities. Purified water enters the faucet or storage tank, and the concentrate containing filtered contaminants is transferred to the drain. In this way, the highest degree of purification up to 0.0001 microns is achieved, which is impossible for conventional flow-type ultra- and nano-filtration systems.
To ensure the purification process, in addition to the thin-film membrane, the membrane filter has several more layers. These layers ensure the movement of fluids in the desired direction and the self-cleaning of the membrane. All layers are rolled up to provide maximum water contact area. The material of the layers determines certain characteristics of the element as a whole: filtration rate, degree of purification, and sensitivity to certain types of contaminants.
The membrane material is typically a Polyamide Thin-Film Composite (TFC). Cellulose film (CTA) is used much less often now, which is inferior in its main characteristics.
The service life of the filters mainly depends on the quality of the water and the intensity of work. For domestic reverse osmosis systems 50 GPD, the recommended membrane replacement time (average) is calculated based on the average consumption of purified water of 10-20 liters per day. For most reverse osmosis membranes, replacement every 1.5 years is recommended. More precise replacement instructions can be found in the manual for the specific filter model.
However, if the filter is operating at its limit of performance, the interval between membrane replacements should be shortened.
The membrane should be changed more frequently if the quality of the source water does not meet the basic standards, or if the replacement interval of the prefilters has been exceeded.
It is quite difficult to fake a reverse osmosis membrane since its production is a complex technological process. However, there were cases when tricksters relabeled membranes, thus passing off inexpensive membranes of low performance as premium models of well-known brands.
Now, most major manufacturers protect their products from counterfeiting in one way or another – most often with the help of original labels with holograms, QR codes and serial numbers.
How do determine – is the membrane originally made or not?
We use the following guidelines from FilmTec and Vontron:
? The “DOW/Filmtec” sticker (classic type) must have a DOW hologram at the bottom and a holographic inscription “GENUINE DOW FILMTEC ELEMENT”, as well as the serial number of the membrane.
? The sticker “DuPont FilmTec” (new type) must have a holographic inscription “GENUINE DUPONT FILMTEC ELEMENT” and a QR code with a link to the website.
Also, plastic tubes should be white (not yellow).
? On the label of Vontron membranes, a lot of information is printed in Chinese. This is normal since the manufacturer is a large and well-established Chinese OEM enterprise. However, there are holograms, a serial number, and a link to the website for verification.
We have not yet come across the non-original new membranes model BW60-1812-75 (99% stabilized salt rejection), since the model is relatively new and less known. Also, cases of counterfeiting of rare brands of membranes, such as Aquaphor and Ionicore, are not yet known. 
Theoretically, it is possible to wash (restore) the used membrane in the reverse osmosis filter with special tools and chemicals. But reverse osmosis membrane cleaners (eg KL-1000) are designed for large professional systems.
In conventional domestic reverse osmosis systems (eg RO-50) 3 pre-filters are installed in front of the membrane. With timely replacement, they sufficiently protect the membrane from contamination and allow it to work for a long time.
Manufacturers of type 1812-50 membranes (Filmtec and Vontron) recommend replacing them after 18 months, and the membranes themselves are inexpensive. It is cheaper and easier than time-consuming flushing.
You can buy water purification systems, filter cartridges (replaceable elements) and related products in the ProMarket-EU online store. We provide delivery of goods to any country in the European Union.
https://market.promarket-eu.com/
How to replace the membrane in a reverse osmosis filter in the right way?
- Find a manual
A reverse osmosis filter usually has instructions that reflect the design features. In case your manual gets lost, here are the basic rules to properly replace the membrane in a reverse osmosis system.
- Replace all filters
The membrane is not replaced alone, but during a “major maintenance”, which involves the replacement of ALL filter elements (pre-filters, membrane and post-filter) and a complete flush of the system.
- Clean vessels
After removing the old filters, all housings, hoses and storage tank must be washed and disinfected. This should be done especially carefully if the filter has not been used for more than two weeks.
- Flush the prefilters
After installing the pre-filters (usually 3 cartridges of a 10-inch drop-in filters), they are washed separately with a continuous flow of water for 15-20 minutes. To do this, use a special flushing valve (if any) or disconnect the tube after the last prefilter.
- Flush the system
After that, the entire system assembly is washed, and 3-4 full tanks of filtered water are drained.
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