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

[aquaman67]

Please post your RO/DI efficiency.

Here's how to figure it out.

Take the line loose that goes from the RO membrane to the DI (not the waste line) and test the TDS.

Next test your tap water.

Now subtract the Pre DI TDS number from the tap TDS number.

Example.

Tap 160 TDS

After RO (before DI) 6 TDS

154 / 160 = .9625

.9625 X 100 = 96.25 % efficient.

I would like to know where you bought your unit and how much you paid for it. Also what TDS meter you are using.

The efficiency when it was new (if you know)

The efficiency now.

How much water you make a week or month.

Thank you.

 

[areze]

this doesnt actually show the life of the filter though... I thought that was the main question.

Ill do it when I get home though

 

[aquaman67]

<a href=showthread.php?s=&postid=12946269#post12946269 target=_blank>Originally posted</a> by areze
this doesnt actually show the life of the filter though... I thought that was the main question.

Ill do it when I get home though

Ok,

If you'd like to change this in some way, that's cool.

My aim was to see what's being sold but if there is another question we can answer for the benefit of everyone, that's cool too.

 

[areze]

nah, cause I dont have any clue how to test for that question anyway. but you said in the other thread you can get RO membranes for 30$, Im interested in that lol, cheaper than ebay!

 

[abulgin]

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

<a href=showthread.php?s=&postid=12946105#post12946105 target=_blank>Originally posted</a> by aquaman67
Please post your RO/DI efficiency.

Here's how to figure it out.

Take the line loose that goes from the RO membrane to the DI (not the waste line) and test the TDS.

Next test your tap water.

Now subtract the Pre DI TDS number from the tap TDS number.

Example.

Tap 160 TDS

After RO (before DI) 6 TDS

154 / 160 = .9625

.9625 X 100 = 96.25 % efficient.

I would like to know where you bought your unit and how much you paid for it. Also what TDS meter you are using.

The efficiency when it was new (if you know)

The efficiency now.

How much water you make a week or month.

Thank you.

Why don't you start? I'll send mine when I get home.

 

[aquaman67]

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

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

<a href=showthread.php?s=&postid=12946588#post12946588 target=_blank>Originally posted</a> by abulgin
Why don't you start? I'll send mine when I get home.

Ok.

I use a Kent Hi-S 60 GPD. I got it Marine Depot in 2002. I don't remember what I paid for it. They are $299 now and I know I didn't pay that much for it 6 years ago. I replaced the membrane after 3 years so that was 2005. The membrane is now three years old again and is 97.6 % efficient.

Tap 168 TDS

After RO only 4.

So it's 97.6 % efficient. It started out at 98.6 % three years ago and when it gets to 96 % I'll change the membrane again.

I use a Hanna Primo handheld TDS meter.

I took down 2 of my tanks when I want to Iraq so I only make about 10 gallons a week now. I used to make a lot more.

 

[abulgin]

Boy, this thread is generating a lot of interest.

So, my tap water has 144 TDS. My post RO water is 4. That means my efficiency is 97.22%.

I have no idea what the efficiency was when the filter was new.

I use the HM Digital DM-1 Dual TDS Meter.

I have a cheap 6 stage (2 DI canisters) 100gpd eBay unit sold by www.purewaterclub.com. I bought it in April 2007 for $76, plus $30 shipping. I hung my DI canisters vertically to maximize the DI pass-through. I have replaced the sediment, carbon and DI filters at about 7 months, and they are due for another change.

I make about 50 gallons of RO/DI water per week.

 

[AD87]

199.00 - OCEAN REEF + 1 FIVE STAGE 75 GPD RO/DI

tds in 145 tds out 1 =99% efficient.
dont know the brand of tds meter but I have called the filter guyz and they swear buy it. I was gonna by one brand new and they said I would waist my money?

 

[poormanisme]

Spectrapure MaxCap 180gpd

before membrane= 232

after membrane=2

efficiency=99.13%

about 4 months old and have made probably close to 300 gallons

 

[Willy315]

TDS Meter try that..

 

[Willy315]

Aqua fx Barracuda bought new on ebay for $110 shipped. Owned 4 years, everything has been replaced. Here's what's in it.

1 micron sediment
5 micron matrikx workhorse carbon filter
75 gpd filmtec membrane
and last stage is DI stage

Tap water 464 tds
After membrane 5 tds or less 99% effeciency
0 tds after DI

 

[abulgin]

Looks like that cheap eBay Barricuda kicks the crap out of the Kent.

 

[unbreakable]

Now:

Ocean Reef + 1

Tap water 700ppm
RO= 15ppm (varies from 12-15ppm)
= 97.8% effiecient

Bought it from www.thefilterguys.biz
$199.00

DM:1 Dual TDS Meter

usually i make about 25-30g a week. It would probably be better if i had a booster pump since the PSI is low in our area

 

[Willy315]

<a href=showthread.php?s=&postid=12948747#post12948747 target=_blank>Originally posted</a> by abulgin
Looks like that cheap eBay Barricuda kicks the crap out of the Kent.

not that it matters but it was just bought on ebay . Its an aquafx brand barracuda

and its not the name that counts as to whats in the filter housings

 

[cabrego]

Wow, I am glad to see my initial thread has lead to a lively debate as well as a nice follow up thread that captures real world performance.

 

[rhoptowit]

i have the melevs one.

tap in @ 275, RO out @ 17.

93.82% effecient, but i have to add the filters are nearly a year old....i gotta change them already.

 

[old salty]

Typhoon III with a BFS 150gpd membrane.

Tap 230
RO 1.6

99.3% efficiency. I run 85 psi using a pressure pump. It makes about 180gpd at 74 degrees.

Meter is an HM Digital COM-100


The efficiency when new was not very good (89%). It took Russ from BFS to find out (over the phone) that the RO housing was cracked on the inside.

The unit makes 120gallons a month.

 

[AZDesertRat]

Spectrapure 100 GPD MaxCap UHE 1:1 waste system running at .5:1 waste or 1/2 gallon of waste for every 1 gallon of good (67% recovery).
Tap water TDS = 835
RO only TDS = 5
Rejection rate = 99.40% efficiency
DI TDS = 18.2 megaohms on a Thornton lab grade benchtop conductivity/resistivity meter and less than 0 on a HM Digital COM-100 handheld meter.

Previous unit was a dual membrane MaxCap at 240 GPD
Tap water TDS = 835
RO only TDS averaged between 5.3 and 6.2
Rejection rate = 99.25 to 99.36%
DI TDS = 18.2 megaohms on the same meters as above and the MaxCap cartridge lasted over 830 gallons before starting to register even 1 TDS.

Before that it was a Watts Premier utilizing all AWI Typhoon cartridges and an off the shelf 75 GPD Dow Filmtec RO membrane.
Tap water TDS = 800+
RO only TDS varied between 13 and 20 but averaged around 15.
Rejection rate = 98% ( I actually live down the street from Watts Premiers factory so they tested the efficiency of the membrane for me after I had a bad one from them which they took back.)
DI TDS was 0-1 at the beginning but became 3-5 after 150 gallons maximum no matter which bulk resin I tried.

With the Watts Premier replacement filters installed the RO only TDS always was over 20 and I did not have DI at that time.

 

[stagefright13]

Great thread! I have a Soumiknight 6 stage that I got from ebay that I didn't get yet. I will test it but will take a few days.

I'll post results from a new one after it is flushed.

These important details are good to know.

 

[carlso63]

Mine is similar to abulgins:

75GPD 6-stage RO/DI from www.purewater.com

Purchased April 2006 for $89; came with a 2nd set of prefilters "free" (as the ad said)

Incoming TDS is 202 - 220 ppm
After RO is 3 - 4 ppm (approx 98.45% efficiency)
After DI is 0

change the prefilters once a year
RO membrane is the original
changed the DI resin at the 16 month mark when output went from "0" to higher than "2" ppm

I make around 60 -70 gallons per week (including top off and water changes)

Only noticeable fault is the advertised 75GPD unit only makes around 60 gallons in a 24-hour period; otherwise has been flawless so far...