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DI COMPARISON CHART -How we stand against the competition!
Here is a list of the known areas that have the most contaminants of arsenic, lead, halo-acetic acids and total trihalomethanes (linked to cancer), and total cloriform bacteria:
WORSE CASE AREAS
NOT TOO BAD
Baton Rouge, LA
Los Angeles, CA
Kansas City, MO
Fort Wayne, IN
Corpus Christi, TX
St. Petersburg, FL
If you are thinking that a standard filter in your refrigerator will be sufficient, think again. The filter in your refrigerator is meant to remove foul tastes and chlorine. It does not reduce the Total Dissolved Solids (TDS) like calcium, magnesium etc. Also to keep in mind, the refrigerator filter does not remove arsenic!
Yes. Your water tastes fine when it is cold, but try tasting your water at room temperature. You'll see the difference.
I should preface this by saying that I have been a long time loyal SpectraPure customer and am posting this inquiry more to educate myself and hopefully others. I should also say that I just purchased 2 additional membranes from SprectraPure before writing this.
I would like to understand how SpectraPure differentiates its membranes (both tested and standard) from others on the market. As consumers what do we enjoy with SpectraPure that we can't get with others? What things do we need to be aware of when buying membranes? What are the specifics that justify the premium cost?
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 web site, 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 same”. 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 ultra pure water. Ultra pure water is about 18.2 mohms or about 0.05 micro-siemens. Most Reefers are after such ultra pure 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, 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.).
1. Trust. Reputation. Quality. Performance.
2. The 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.
3. A 2% loss of rejection costs you more money in the long haul with twice as many DI cartridge changes required from 2% less rejection.
4. All of the membranes SpectraPure sells are treated with a proprietary process to enhance % rejection and production characteristics.
5. We 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).
6. We individually test and guarantee our Select (-s) membranes to be greater than 98% rejection.
7. On 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.
8. Production rates on our membranes often exceed stated GPD due to our proprietary treatment process. For example, our 90GPD often exceed 100 GPD.
Ice makers usually need at least 30 PSI to operate. If you are supplying RO water to your ice maker, you may have a problem.
The pressure of the RO water leaving a pressurized storage tank is dependent on the incoming tap water pressure. The pressurized tank will have about 1/2 - 2/3rds as much pressure as compared to the incoming tap water pressure. For example, If you tap water pressure is at 50 PSI, then the tank pressure will be about 25 PSI. Make sure when you are supplying water to an ice maker, that you have sufficient pressure for the ice maker to function.
IF YOU HAVE A PROBLEM WITH YOUR ICE MAKER DUE TO LOW PRESSURE, PLEASE CALL FOR AN ALTERNATIVE SOLUTION.
Flushing the membrane helps to prevent membrane scaling and plugging, when a system is used in an area with particularly high TDS, or hard water. A system run at a low ratio eg. 2:1, will greatly benefit from employing a flush mechanism , especially in cases where such use is under aformentioned conditions. Read this article from DOW in regards to why it is beneficial to flush - Article...
I wanted to take some of your time to explain and clarify why our new membranes with 99% typical rejection are so important to your RODI system water production efficiency and a lower cost of operation.
In the old days, vendor specs for the "best" membrane were 96% minimum, and 98% typical.
Of course there were a few with much better rejection in these large batches of membranes so SpectraPure® individually tested each of these membranes to select only a few having the best performance to sell as our "SpectraSelect™” >98% rejection (guaranteed). Those that did not make the grade were used in less critical applications, or if below the manufacturers spec, returned to the supplier.
Around this same time, SpectraPure also developed an in house proprietary treatment process to enhance rejection, increase production, and decrease rinse up time. We still use this process today, regardless of what membrane source material we use as the benefits are substantial for high purity water production.
These original SpectraSelect membranes could easily provide a customer with a 2% rejection increase over the bottom end of the specification of the leading membranes of the day (96% rejection being the bottom end of the spec, and >98% rejection being our treated, individually tested and verified guarantee).
You may ask why 98% rejection vs. 96% rejection is even that important, and how could such a seemingly small 2 % increase possibly save you money in operation costs?
Case#1 Impact of going from 96% to 98% rejection on typical feed
Raw Water TDS
In this case, going from 96% to 98% rejection increase cuts in half (10.8ppm down to 5.4ppm) the ionic load passed on to the DI section of your RODI system. Cutting this load in half in effect DOUBLES the life of the DI section. In other words, cuts in HALF your DI costs.
Now, the best just got better…The New SpectraSelectPlus™ 99% Rejection Membrane
Our new 99% rejection SpectraSelectPlus™ membrane blows away the competition. It is simply the best available membrane for the money.
Our newest membrane is treated with our in house proprietary process to enhance rejection, increase production, and then individually tested to guarantee a minimum of 98%, with typical 99% rejection!
Is a one percent increase over our old SpectraSelect membrane really worth it you ask? Refer to case #2 below; showing a one percent increase at these high levels of rejection DOUBLES the life of your DI! Or in other words cuts your DI costs by half!
Case #2 Impact of going from 98% to 99% rejection on typical feed
Raw Water TDS
As usual, there is a competitor offering a “me too” “99%” rejection membrane, but looking closer, their spec is a minimum of 97%. Again, our SpectraSelect membrane has a minimum of 98% rejection, or at least one percent more than this competitors membrane. Refer to case #3 below In the case of going from 97% to 98%, this is a minimum improvement of 1.5 TIMES the life of the DI section. Still a significant cost reduction.
Case #3 Impact of going from 97% to 98% rejection on typical feed
One and a half
But what if you only have 97%rejection and you upgrade to 99% with the SpectraSelectPlus?
Case #4 shows if you go from the minimum competitor rejection spec of 97% to our typical SpectraSelectPlus™ 99% rejection, a TRIPLE life increase in your DI. Triple!
Case #4 Impact of going from 97% to 99% rejection on typical feed
Raw Water TDS
What if you only have 96% rejection now, what will 99% rejection do for your operating cost?
To answer the question of those whom have the fairly typical industry standard 96% rejection membrane, a 99% rejection membrane will quadruple Your Di life. Let me repeat, quadrupled. Please refer to case #5. This is a strong case for keeping the best membrane in your system possible. Improved Rejection performance pays huge dividends in DI life!
Case #5 Impact of going from 96% to 99% rejection on typical feed
Raw Water TDS
When should I change my membrane?
The flip side of this question is when should I change my membrane? Refer to case #6 which shows the impact of your rejection degrading from 98% to 95%, DI life is cut in half.
Case #5 Impact of going from 98% to 95% rejection on typical feed
Raw Water TDS
Increase in Ionic Load
Note: these calculations assume no CO2 which is not removed by your RO membrane, which can significantly degrade the life of your DI. High pH, or contaminates such as chloramines will also affect performance. The typical calculation charts shown reflect the IONIC load improvements relative to each Rejection Improvement.