Whats so special about spectrapure membranes?

Summary
oTrust. Reputation. Quality. Performance.
oThe lower % rejection limit for most reputable RO membrane manufacturers is 96%. So even if you are buying a “98%†rejection membrane from our competition, you may actually receive a 96% rejection membrane.
oA 2% loss of rejection costs you more money in the long haul with twice as many DI cartridge changes required from 2% less rejection.
oAll of the membranes SpectraPure sells are treated with a proprietary process to enhance % rejection and production characteristics.
oWe batch Q/C test our standard membranes to insure that within batch rejection and production variation is within manufacturers specifications. As a result, we actually reject some membranes and do not sell them to you. (They go to non-critical applications).
oWe individually test and guarantee our Select (-s) membranes to be greater than 98% rejection.
oOn spectra Select (-s) membranes we individually test and then write the actual performance on the membrane. You get in writing exactly what you paid for.
oProduction rates on our membranes often exceed stated GPD due to our proprietary treatment process. For example, our 90GPD often exceed 100 GPD.


First, some useful background from our prior posts-
The RO membrane is the workhorse of the water purification system. It uses a thin film membrane technology to reject impurities. RO membranes are especially good at rejecting large atoms and molecules and those species that exhibit relatively strong electron charge. It is less effective in rejecting small atoms and molecules (smaller than water) and those with relatively weak electron charge. RO membranes will allow all dissolved gases (such as ammonia and carbon dioxide) to pass through. The % rejection rating for a membrane is an indication of how much of these impurities will pass through the membrane and on to the DI cartridge. A membrane that has a 98% rejection rating will pass only half as many of these impurities as one with a rating of 96%. The direct result of using a 98% rejection membrane as opposed to a 96% membrane is that you will double your DI cartridge lifetime. It is important to note that all membrane manufacturers adhere to a lower % rejection limit for small membranes (2" x 10") of 96% at 60 psi and that the only way to ensure that you are using a higher % rejection membrane is to purchase it from a source which screens for higher % rejection membranes. Spectrapure’s membranes are treated with a proprietary process to enhance % rejection and production characteristics. We have been testing our RO membranes for over 20 years to the industry standard of 60psi. There is a significant amount of data for us to draw upon when we share performance characteristics with our customers, help them troubleshoot production problems, or back up our ratings claims, for that matter.
Production rates are another source of confusion. For example, the Filmtec 75 GPD membrane that is so popular is rated 75 GPD at 50psi. When we test it at the industry standard of 60 psi, the rating is at 90 GPD. The production rate of RO membranes is directly proportional to the applied pressure, thus the rating difference; this is why we sell our membranes and systems as 90 GPD (at 60 psi and 77F). Unfortunately, most customers in the USA have less than 60 psi (or even 50 psi) available, let alone the 77F water temp that is used in the rating process (average water temp is more like 50F across most parts of the country). In these cases a pressure-boosting pump can obtain higher production rates. If you live in Hades (Phoenix in the summer) the 77F is not much of a limiting factor as far as production goes. But for our customers in upstate New York in January, it is a huge factor. Perhaps to be more realistic we should all rate membranes production on systems at 40 psi and 50F, although I doubt our competitors would drop their rating convention in this highly competitive market seemingly driven by perceived cost per gallon production rate.
That said, with the membranes that we hand-select and test to insure rejection greater than 98%, we typically see production rates exceeding 100 GPD at 60 psi (and 77 F)!! If you look back at their literature, Filmtec may have started the 50 psi rating as a sales gimmick wherein they stated that FILMTEC membranes have the same production at 50 psi as the competitors membranes do at 60psi. Great way to snag customers, but it requires customers to look at the production rate charts and how they are derived to really compare membrane production rates. With our hand-selected and tested Filmtec 75GPD membranes, we can make sure that you are purchasing greater than 98% rejection (look at their spec on the DOW website, 96% is the bottom range of the guarantee. They are not all 98% like many think). http://www.dow.com/liquidseps/prod/tw30_181275.htm Also, even more astounding, is that with the membranes that we hand-select and test to insure rejection greater than 98%, we typically see production rates exceeding 100 GPD at 60 psi (and 77 F) !!


Why is 1 or 2% so important?? A 2 % increase in rejection from 96% to 98% can double your DI cartridge(s) life. Over the life of the membrane that can save you big $$$ in DI cartridges! That is why our hand selection and proprietary testing (we sometimes reject more than half that do not meet our SPEC of >98.0% rejection) is worth the extra cost. Who else labels their membranes with actual rejection rate on the so called "the same" membrane?

Our experience has been that RO membranes are not “all the sameâ€. That’s why we back up with science the performance of our membranes which are a critical element in the performance of your system, albeit removal of harmful species or your cost to operate your system. Rejected membranes are sold to another, far less demanding market. The difference in price reflects some of our investment to perform the testing. The price difference between an untested and a tested membrane is lost in the savings if you obtain 1 or 2% improvement in rejection as your DI stage(s) life is drastically improved. Even our untested membranes are subjected to a proprietary process which increases their rejection ratio over the units purchased by other vendors from the same supplier. So, those who claim that all membranes from a particular vendor are the same may not be aware of our process by which we routinely see our average rejection increase over non treated units. DI cartridges are one of the highest operation cost factors for your system per gallon of water produced, thus our customers tell us the extra price paid is well worth the return from savings on Di. Others just want the best to take water production quality out of the equation as much as possible from their aquatic environment maintenance equation.



A quick note on how people often compare system performance in the field using common instrumentation:
I thought I would comment on the common misnomer "ZERO TDS". Persons stating ZERO TDS I assume are referring to Zero Indicated TDS. What's the difference you ask? Well, quite a bit when you are really talking about ultrapure water. Ultrapure water is about 18.2 mohms or about 0.05 microseimens. Most Reefers are after such ultrapure water in our experience. Thus, if there were such a thing as "ZERO TDS", it might be more appropriately measured around 0.05 micro siemens. Unfortunately, most (not all) inexpensive TDS meters can resolve at best about 5 micro seimens. That is several decades less sensitivity than required to be stating so called "ZERO TDS".

While 5 micro siemens conductivity (at an affordable price and rugged instrument easily operated and maintained) is very reasonable for for break-through detection to signal cartridge replacement required, it is clearly not sufficient to measure or crow about having “ZERO TDS†. Thus, postings where one has "measured" a system or component performance and state they have "ZERO TDS" should be careful to quantify the accuracy of the instrument they are using to make such a claim. Hopefully this will shed some light on... zero is not always zero.

In closing, we are not a company that simply buys from one source and sells to another. Critical Products like membranes, DI cartridges, filters, housings,gages, valves, pumps and pretty much everything we make or sell are exhaustively tested and analyzed in the lab and then in the field to make sure they meet our performance standards before you make your purchase. When you buy from us, you also get over twenty years of field experience. We have many unique technologies evidenced by our growing patent portfolio and a steady release of new products each year (the Silica Buster, teh spectra select membranes, the Liter Meter, the MaxCap, the CLS, the UHE and more to come!) Simply put, we see ourselves as innovators trying to bring you the best performance products for the dollar, as in our experience "quality is remembered long after price is forgotten...).
bruce