Comprehensive RO/DI efficiency study, especially e-bay units.

[areze]

from the looks of this thread, there are no "better filters"

we are all within like 2%... everyones RO is getting their output under 5TDS save for the 1 guy up there with low water pressure.

the thread appears to basicly say they are all equal as far as how long your DI will last. it doesnt say how long your RO will last though, which I thought was the real question... I cant imagine anyone actually records total volume of water that they make.

[aquaman67]

The point I'm really trying to make is consistency.

Here's a purewaterclub unit on ebay.

http://cgi.ebay.com/New-Reef-6st-100...QQcmdZViewItem

From their own web page:

Water Purity Reference: (1.)Tap or well water(300 PPM), (2.)After RO system(20 PPM)

So that's 93% efficiency. They don't tell you that and unless you do the math you'd never know. They don't just come out and say it's only 93 % efficient. And that's what I don't like about ebay. You have to know what you're looking at or get lucky. The 75 GPD units seem to work better than the 100 GPD units.

[FB]

I bought an ebay unit two years ago.

TDS in 155
TDS out 4.
I use a milwaukee tds metre.

97.4%

I paid $99.00 from filter direct.

[areze]

Originally posted by aquaman67
The point I'm really trying to make is consistency.

Here's a purewaterclub unit on ebay.

http://cgi.ebay.com/New-Reef-6st-100...QQcmdZViewItem

From their own web page:

Water Purity Reference: (1.)Tap or well water(300 PPM), (2.)After RO system(20 PPM)

So that's 93% efficiency. They don't tell you that and unless you do the math you'd never know. They don't just come out and say it's only 93 % efficient. And that's what I don't like about ebay. You have to know what you're looking at or get lucky. The 75 GPD units seem to work better than the 100 GPD units.

I honestly dont understand what that part means on their listing.

but by the RO filter they say, removes 98% to 99.99% of all chemical and harmful dissolved elements and 99% of all bacteria. seems to indicate ~98% efficiency then. which is about what we are seeing here.

[AZDesertRat]

This thread is somewhat pointless as it takes months to years to see the effects of cheap prefilters and carbons on the life of an RO membrane. In my case at 835 TDS tap water the effects can be seen in weeks or a few months at most. With a TDS of 100 it would not be so obvious but the effects are still there. The point is using better quality filters will improve the lifespan and longterm performance of a membrane and this is proven time and again. I look at a RO/DI system as a "tool" and I take care of my tools. I fully expect to have the same unit with the same membrane around for years and years, so I use only high quality replacements.

If I figure cost of ownership over a 6-10 year period I am money ahead by doing so. In a normal system you can expect a maximum lifespan of a membrane to be 3 years. With my old system I averaged 18 to 24 months per RO membrane. I expect to see 9-10 years on mine now. Randy Holmes Farley just reported 10 years on his original Spectrapure RO membrane.

With a 96-98% rejection rate RO membrane I can expect to see about 150 gallons per 20 oz refill of good quality mixed bed DI resin based on my personal testing and what I hear from my fellow reefers in the Phoenix area. By using the good filters and the Select membrane I am averaging well over 800 gallons per DI cartridge using Spectrapures resins.

Using those numbers I figure I will save the cost of 3-5 replacement RO membranes and 50 to 100 DI cartridges in a 6 to 10 year period based on 150-200 gallons of DI per month.

Yes my prefilters, carbon blocks and DI cartridges cost more to replace but if I am saving that many replacements I am still way ahead in both dollars and labor expended. Its a win win situation for me!

[aquaman67]

Originally posted by areze
I honestly dont understand what that part means on their listing.

but by the RO filter they say, removes 98% to 99.99% of all chemical and harmful dissolved elements and 99% of all bacteria. seems to indicate ~98% efficiency then. which is about what we are seeing here.

Right,

To me it's mis-leading to say the least.

I guess I'm not being clear. There is a difference in what you can get, membrane wise. I'm sure there are people who have the less efficient membanes who haven't or won't post their results here. That's how the thread I mentioned in the archives from a few years ago got started in the first place. People were complaining about burning through DI resin. After I saw their site and did the math I figured out what was going on. After that people asked for true RO membranes. I didn't find filter direct on ebay. Maybe they stopped selling on ebay?

[AZDesertRat]

Honest vendors use the published figures provided by the membrane manufacturer and do not make up facts and figures out of thin air.
I see two red flags here.
One is they are being deceptive and contradictory as to the performance and are afraid to publish real factual numbers and two is they are using no name products otherwise they would be proud to publish who makes their components and how well they work. Dow, GE and Applied have tested their membranes for years and have volumes of published data that is available to their resellers for promotional materials. No need to make numbers up.

If you were selling a product which was made up of name brand internationally famous parts and pieces wouldn't you state those names in your advertising to draw in customers??? Most of us are very observant and are looking for the best product at the best price. If I can sell you a XYZ RO/DI using the same components as Joe Schmoe but at a significant cost savings don't you think I am going to promote my product accurately?

What seems to be overlooked is quality costs money. Even in huge volumes a Dow membrane or Matrixx+1 carbon block is going to cost more than an untested and uncertified imported product. Companies pay large sums of money to get a product ANSI/NSF certified and it has to be passed on to the consumer. This certficiation is for our protection and is important. Its just not possible to construct a RO/DI unit using quality components and sell it for $89 when a membrane alone costs $30 at wholesale even by the truck load. Add in quality prefilters. carbon blocks, housings, cartridges, DI resin, valves, fittings and gauges and it all adds up.

[bubble girl]

I got a RO/Di from ebay-filterdirect, It was a 100 GPD model. My tap water TDS is about 200. After Ro only it was 20 TDS. It’s about a year old. 90 % efficient by aquaman’s calculation formual. I am going through Di media faster than I think I should so I’m going to buy a new unit as soon as I can. I hate those little Di canisters anyway. It won’t be from ebay but from a sponsor of R/C. I’ve learned so much from here. Thank you aquaman and AZDesertRat.

[areze]

true the guy on ebay doesnt list the part.

but I do have the part in my hand, so I know what it is... I posted it in the other thread. forgot what it was now though. looked to be ok.

[AZDesertRat]

I believe you said Ultratec or something and the part number did not match up with a Dow Filmtec product if I remember correctly.

Ultratec is in fact a legitimate California company but I cannot find any mention of NSF certifications or testing on their membranes.

Pirates and knock offs take advantage of trade names by making items appear similar and names sound close to the same. This is another misleading technique they use. Change things just enough so you don't get sued, not that they can stop a pirate in China anyway.

[RichConley]

Originally posted by AZDesertRat

If I figure cost of ownership over a 6-10 year period I am money ahead by doing so. In a normal system you can expect a maximum lifespan of a membrane to be 3 years. With my old system I averaged 18 to 24 months per RO membrane. I expect to see 9-10 years on mine now. Randy Holmes Farley just reported 10 years on his original Spectrapure RO membrane.

Bought my ebay unit in 2003. Still kicking with the original membrane, still 98%+.

[RichConley]

Originally posted by bubble girl
I got a RO/Di from ebay-filterdirect, It was a 100 GPD model. My tap water TDS is about 200. After Ro only it was 20 TDS. It’s about a year old. 90 % efficient by aquaman’s calculation formual. I am going through Di media faster than I think I should so I’m going to buy a new unit as soon as I can. I hate those little Di canisters anyway. It won’t be from ebay but from a sponsor of R/C. I’ve learned so much from here. Thank you aquaman and AZDesertRat.

All you need to do is replace the DI cannister and the membrane. $30 for a filmtech 75gpd (from any number of sponsers) and another $30 or so for the DI 10" cannister and refillable cartridge. Theres no reason to replace everything. 10" Cannisters are 10" cannisters.

[areze]

Originally posted by AZDesertRat
I believe you said Ultratec or something and the part number did not match up with a Dow Filmtec product if I remember correctly.

Ultratec is in fact a legitimate California company but I cannot find any mention of NSF certifications or testing on their membranes.

Pirates and knock offs take advantage of trade names by making items appear similar and names sound close to the same. This is another misleading technique they use. Change things just enough so you don't get sued, not that they can stop a pirate in China anyway.

yeah, that sounds right, the ultratec part. when I typed in the part number I found an ultratec spreadsheet though, which "equated" their filters to the other guys, like this is our equivalent of that, not that I put a lot of faith in a companies datasheets, tend to be biased.

the filter number that didnt match up was the BFS RO filter number, was not on filmtec's listing, I later realized this was because BFS was not showing the real part number either. they used a BFS part number. I think it was safe to presume it was he 75gpd membrane that ultratec had matched to it, it was the only 75gpd drinking water membrane as far as I could see from filmtec.

[AZDesertRat]

Dow Filmtec membranes are usually a TW-1812-XX with the XX being 50, 75 etc. Some units use a less common TW-1810 series which is not interchangable, these include Whirlpool, Lowes, Sears and some Watts Premier products.

Companies which carry a NSF certification provide very accurate data as it is a very important part of that testing and certification process. This process can take several months to a couple years to complete, is very rigorous and very expensive. Both Dow and GE/Desal have good charts showing removal efficiencies of various solutes and the effects of temperature and pressure on a membrane. Good info for sure.

[abulgin]

Mine is a TF-1812-100

[areze]

thats what mine is as well, google indicates it to be the ultratec.

[Randy Holmes-Farley]

Water temperature, line pressure, and what's in the water impact RO efficiency, so even if folks had perfect TDS measurements, I think making comparisons between different users is going to be tricky to interpret in a thread like this.

[Willy315]

Originally posted by bubble girl
I got a RO/Di from ebay-filterdirect, It was a 100 GPD model. My tap water TDS is about 200. After Ro only it was 20 TDS. It’s about a year old. 90 % efficient by aquaman’s calculation formual. I am going through Di media faster than I think I should so I’m going to buy a new unit as soon as I can. I hate those little Di canisters anyway. It won’t be from ebay but from a sponsor of R/C. I’ve learned so much from here. Thank you aquaman and AZDesertRat.

100 gpd membranes have a lower rejection rate than others, typically 90% which is roughly what you are seeing with your unit

[aquaman67]

Originally posted by Randy Holmes-Farley
Water temperature, line pressure, and what's in the water impact RO efficiency, so even if folks had perfect TDS measurements, I think making comparisons between different users is going to be tricky to interpret in a thread like this.

True...this is hardly scientific.

This page

http://www.aquacave.com/dow-100-gpd-...rane-1822.html

List TF-1812-100 as a DOW filmtec membrane.

Makes you wonder....

[AZDesertRat]

100 GPD membranes are not always less efficient but that is the case with the Dow Filmtec TW-1812-100. In the case of Ultatecs TF-1812-100 it should really be compared to Dow Filmtecs TW-1812-75 not the 100. Ultratec claims 100 GPD at 60 psi and 77 degrees which is similar to Dows 75 GPD membrane when you increase the pressure from their figure of 50 psi up to 60 psi. The rejection rate should be 96-98% not 90% but I could not find the data on their website to back that up.

AquaCave is Aqua FX and looking further at their various sites and pages I see different conflicting information like Ultratec part numbers coupled with pictures of Dow membranes and other things like Aqua Engineering brand "made with genuine Dow materials" etc.

[areze]

interesting, but yeah, it isnt. thats not what ours look like anyway. the label I mean. and we know dow doesn label like that either.

Id say its shady, but that depends what that site actually sent you... 49.95 isnt a great price for either one though, so kind of a mute point.

[abulgin]

So, here is a picture of what I did to my eBay unit to make the DI filters more effective.

[AZDesertRat]

Fill your DI cartridges completely full and they will work much better. Fill them, tap them on the table top, fill again, tap again and do a final fill before replacing the sponge and that way the water has longer contact with resin. Guaranteed to function better and longer.

[abulgin]

thanks. will get some more resin and fill it up!

[carlso63]

I look back a day later, and now I can see the real purpose of this "Comprehensive Efficiency Study" is yet another thinly disguised "bash" thread...here we go again

I, for one really don't give a rat's buttocks what the wording on some advertisement says; I care how the thing performs...

I get a 98+% rate on my eBay unit - that is my real world experience. I could care less if some idiot ad writer figured it out to be 90% or 93% or whatever; and, most importantly, that rate is DAMN CLOSE to the rate of the more expensive units - so stop arguing that you half a percent higher rate is sooo soooooo much "better" - because it ISN'T... and the amount of "longer life" you get out of your DI resin isn't significant, cost-wise... unless you are are AZRat who has up to 1300 ppm most days where a half percentage point might be 7 - 10 ppm difference after RO - for basically everyone else a half percentage point higher rate equates to less than 1 ppm difference post RO so you will use up your DI resin at almost the exact same rate that I will...

My unit takes my 220ppm tap down to 4ppm after RO and the DI brings it to 0. And YES, I reoriented my DI cartridges, too... funny how that is considered "having to fix it to get it to work" here and not "modding" for better performance like any one of the hundred some-odd other "fixes" we as hobbyists do all the time to our skimmers, or powerheads, or light fixtures and yes, our water purification units -

And despite all the hype about filters, the TRUTH is that just about ALL of us - with the possible exception of AZDesertRat - all of us will end up changing our filters as part of "routine maintenance" (like once a year or once every 6 months, for example) and NOT because "...the cheap filters don't last as long as the expensive ones"... I change my prefilters once yearly; if I decided to "upgrade" to the "premium quality" brand filters I WOULD STILL CHANGE THEM ONCE A YEAR. No Difference.

And, when the dust settles, the 0 ppm I am getting out of my unit is the SAME as the 0 ppm you are getting out of your unit - no matter what psuedo scientific terminolgy you pull out of your whazoo - ZERO TDS IS ZERO TDS. PERIOD

And the main driver behind unit choice should be the incoming (tap) TDS level of the user. There is no need whatsoever for someone who is getting 50, 100, even 200 ppm out of their tap to feel they HAVE to have a premium unit in order to have "safe" water for their Reef... that is just baloney. Of course, if they CHOOSE to own the best unit money can buy, that's their right and that's fine - but they don't NEED to. And they should stop inferring that everyone else "needs to" as well...

Conversely, someone like AZDesertRat DOES NEED TO use a premium unit. My ebay job wouldn't last a week with his 800-1300ppm tap water. So he, in effect, actually has less of a choice because of his harsh water supply.

And this glorified peeing contest over which choice is "better" really doesn't change the facts one bit...

So, are we done with this yet?