Ebay RO/DI Units...

[RobbyG]

<a href=showthread.php?s=&postid=9751295#post9751295 target=_blank>Originally posted</a> by carlso63
Interesting to note that in "The Consciencious Marine Aqaurium" the opinion on using RO/DI water at all is basically that it is "...overrated as a panacea for aquarist's problems...in the vast majority of the country (U.S.) Bombs Awaaaaaaaay!

:uzi: :hammer: :blown:

I own that book and found it to be pretty good. Problem is:
Did you look at the date it was published? 1997!
Back then there was not a lot of consensus on many issues and Ro was one of them. It turns out he was dead wrong, clean FW is a key shot too keeping corals alive. Nobody in this thread is debating the fact that Low TDS FW is good for corals, as a matter of fact I don't think you will find a single thread on RC that says Higher TDS is OK. Most people know that if your RO dumps even 3-5 ppm in your tank you will start to see Algae growth increase. So there is no argument anymore on this issue.

 

[TwistedTiger]

<a href=showthread.php?s=&postid=9748659#post9748659 target=_blank>Originally posted</a> by RobbyG
This is exactly what the self proclaimed experts are saying and you just proved their point. I have been running a Typhoon 3 for 18 months and I have not had to replace any filters or the membrane yet. The only thing I did was refill the DI resin about 4 months ago when the TDS crept up to 3ppm. On the other hand you are now buying all new filters, buying an new membrane and a new DI cartridge. Thats almost a whole new unit in just 18 months. Were have the saving gone to

You obviously don't understand how an RO/DI filter works, anyone can change just the DI and get back to zero, that doesn't mean your filters are still good. The carbon prefilters are rated for so many gallons and should be changed when needed, just because you now get a 0TDS again doesn't mean your prefilters are not used up.

I also stated in my post that I used the oppourtunity to upgrade all filters and the membrane and still had not reached the costs of some of the high end units origional cost. I also have enough DI resin to refil my cartiges about 4 more times. I didn't NEED to change my membrane I simply chose to upgrade form 100gpd to 75gpd while making the order for more filters and DI from the filter guyz.

I'm very glad you and some of the others are happy with your high dollar units I just don't understand the need to bash lower cost units that produce quality water at a much much cheaper price even over the long haul.

 

[AZDesertRat]

Look at what year that book was written in. Talk to Bob today and ask his opinion now. RO/DI was in its infancy at that time and was not fully understood as far as reefkeeping.

I will still lump almost all ebay units together. Just like anywhere else ther are exceptions but they are few. AquaSafe while a step above Filter Direct is still an inferior unit for reef keeping. If they want to compete with true reef systems they need to drop the cheesy granular carbon cartridge thats almost totally worthless, even for drinking water and add a true 10" canister and cartridge type DI filter. What would it cost them, maybe $5 at the whoesale level? As long as they include sub par components they will be a sub par unit plain and simple.

Yes some or all of RC vendors offer cheaper units but you will never find me recommending them. I know for a fact when you call and talk to them explaining your needs they will do all they can to talk you out of the less expensive units if you tell them "reef". Most are saltwater hobbyists themselves and understand the needs.

As for DI resins and brands there are literally hundreds of resin blends from just Purolite alone. Dow also manufacturers resins and offer dozens and dozens themselves. It takes someone like Spectrapure who custom blends the resins in their cartridges to exactly fit the varying needs. No one else does this and thats why the MaxCap and Silica Buster cartridges are unlike any other cartridge on the market. No one else custom blends and layers resins to take advantage of pH changes within the resin bed, no one. Yes you pay for this service but it pays off in the end with greatly extended life and superior water quality not attainable with normal "store bought" resin cartridges and refills. I have proven this with a lab grade Thornton bench top conductivity/resistivity meter and later with my COM-100 meter.

Spectrapure is also the only company offering absolute rated filters instead of nominal rated filters. Again you probably don't understand the difference and will argue the point but it makes a difference. As for RO output, I have never seen a SpectraSelect membrane put out a TDS of anywhere close to 20. My tap TDS exceeds 850 and I get 6.2 to 6.4 within seconds of turning it on even with normal TDS creep. You can't compare them to anything else.

You can argue all you want but you are barking up the wrong tree. THERE IS A DIFFERENCE IN RO/DI UNITS PERIOD.

 

[TwistedTiger]

<a href=showthread.php?s=&postid=9751568#post9751568 target=_blank>Originally posted</a> by AZDesertRat
You can argue all you want but you are barking up the wrong tree. THERE IS A DIFFERENCE IN RO/DI UNITS PERIOD.

I agree, some are waaaaay over priced!!!!
Just kidding, I never said there wasn't a difference, just that some of the lower priced ones are more than sufficient.

 

[AZDesertRat]

You're wrong. I can show you on paper they are not efficient and they cost you more to operate. My MaxCap will return the difference in cost in the first year alone and I have the numbers to prove it for those who are truly interested and not just wanting to argue.

 

[BeanAnimal]

Groundhog day...

That is what these threads remind me of.

Each page is the same as the last, each thread is the same as the last.

Bean

 

[MusMusculus]

<a href=showthread.php?s=&postid=9751608#post9751608 target=_blank>Originally posted</a> by AZDesertRat
You're wrong. I can show you on paper they are not efficient and they cost you more to operate. My MaxCap will return the difference in cost in the first year alone and I have the numbers to prove it for those who are truly interested and not just wanting to argue.

I'm interested in seeing those numbers. My tap TDS is 33 (Seattle, WA). Is it worth it to invest in a "BigBoy" unit? How long before that investment is recouped?

 

[AZDesertRat]

How much water do you make?

 

[RobbyG]

<a href=showthread.php?s=&postid=9750724#post9750724 target=_blank>Originally posted</a> by Colin
I think dismissing all units sold on Ebay while promoting the units sold by sponsors is an injustice too. Obvously, some Ebay companies (like Aqua Safe) make a good quality, effective unit, and several of the sponsors sell some really low end stuff (like a carbon filter + a membrane).

We really should be talking about individual products here, and not about where they're sold.

--Colin

Colin if you step back and look at the structure of Ebay you can understand why we just label it as "Ebay".
When you go to ebay and type in Ro Di filter you get lots of hits, all of them from competing companies that are mostly selling one brand "Dvoneb". It may come in a whole bunch of pretty looking flavors but underneath is that same craptastic filter. The other companies are all trying to compete so they make filters that can come close in price but they have to skimp on quality to compete with the other stores. I agree there are one or two good filters in the lot but if you look at there prices you would be better off dealing with a know vendor than dealing with a company that often times does not even have a phone number.

 

[MusMusculus]

AZ,

Very little currently (29g nano), but I expect to need about 50-75 gallons per week soon (buying a used 180).

 

[RobbyG]

<a href=showthread.php?s=&postid=9751516#post9751516 target=_blank>Originally posted</a> by TwistedTiger
You obviously don't understand how an RO/DI filter works, anyone can change just the DI and get back to zero, that doesn't mean your filters are still good. The carbon prefilters are rated for so many gallons and should be changed when needed, just because you now get a 0TDS again doesn't mean your prefilters are not used up.

I understand it perfectly, you can take straight Tap water and throw it into a can of DI resin and get Zero TDS, Duh Duh that's Filter 101. What I am saying is that after 18 months my prefilters do not look even 10% as dirty as yours and my Ro resin is still producing 5ppm as it did when I first started. The reason my Prefilters are not as dirty is partly due to the fact thay they are 2 times bigger that the Dvoneb prefilers and that equates to whole bunch of times more surface area. My RO filter is still good because it's of a much higher quality than the one's supplied with the Dvoneb units. The DI will always get used up becasue the 5ppm is leeching it down slowly, but thats the only thing that needs changing and I dont have to throw away the whole cylinder, I just open it up pour out the DI and replace it from a 5lb bag that I purchased.

 

[Reefugee]

Rob,

As promised, I just re-did the RO water reading. According to the inline TDS meter, the water was 3ppm. I went ahead tested the same water with a handheld water meter, and it measured 6ppm. Ironically, when I put the inline TDS meter's probe into the water container, it reads 6ppm. I confirmed this measurement twice. The two containers were the "sterile" medical containers.

Here is my newest reading:
Tap water: 545 ppm
RO water: 6 ppm (see above)
DI water: 0 ppm verified with inline TDS meter and handheld meter

RO membrane efficiency: 98.9% rejection rate


Minh

<a href=showthread.php?s=&postid=9748415#post9748415 target=_blank>Originally posted</a> by RobbyG
Something must be wrong with your numbers, I don't think it's possible for an RO membrane to take the water from 546ppm down to 2ppm. That Rejection rate exceeds any figures I have ever seen. I suspect your meter is inaccurate which would mean all your conclusions are inaccurate.

 

[RobbyG]

<a href=showthread.php?s=&postid=9751636#post9751636 target=_blank>Originally posted</a> by BeanAnimal
Groundhog day...

That is what these threads remind me of.

Each page is the same as the last, each thread is the same as the last.

Bean

Yep, that's why I normaly avoid these threads.

 

[TwistedTiger]

<a href=showthread.php?s=&postid=9751850#post9751850 target=_blank>Originally posted</a> by RobbyG
What I am saying is that after 18 months my prefilters do not look even 10% as dirty as yours and my Ro resin is still producing 5ppm as it did when I first started. The reason my Prefilters are not as dirty is partly due to the fact thay they are 2 times bigger that the Dvoneb

You can't just look at a carbon prefilter and tell if it's spent, Duh that's filters 101. I'm not using a Dvoneb filter so you have no clue how dirty MY filters are.

 

[RobbyG]

<a href=showthread.php?s=&postid=9751900#post9751900 target=_blank>Originally posted</a> by Reefugee
Rob,

As promised, I just re-did the RO water reading. According to the inline TDS meter, the water was 3ppm. I went ahead tested the same water with a handheld water meter, and it measured 6ppm. Ironically, when I put the inline TDS meter's probe into the water container, it reads 6ppm. I confirmed this measurement twice. The two containers were the "sterile" medical containers.

Here is my newest reading:
Tap water: 545 ppm
RO water: 6 ppm (see above)
DI water: 0 ppm verified with inline TDS meter and handheld meter

RO membrane efficiency: 98.9% rejection rate


Minh

6 ppm sounds a lot more realistic than 2 ppm but i suspect it's really more like 10-12ppm. Problem is all these TDS meters that most of us own are very inaccurate. You would need one of the good one's like BeanAnimal and AZ have if you wan't accurate readings. Are they worth the money? Nope! Not unless your a water expert like those dudes

 

[RobbyG]

<a href=showthread.php?s=&postid=9751942#post9751942 target=_blank>Originally posted</a> by TwistedTiger
You can't just look at a carbon prefilter and tell if it's spent, Duh that's filters 101. I'm not using a Dvoneb filter so you have no clue how dirty MY filters are.

Not talking about the carbon Prefiler, I am talking about the Sediment filter. I thought you were the one who posted the picture, that was my mistake.

 

[Colin]

<a href=showthread.php?s=&postid=9751964#post9751964 target=_blank>Originally posted</a> by RobbyG
6 ppm sounds a lot more realistic than 2 ppm but i suspect it's really more like 10-12ppm. Problem is all these TDS meters that most of us own are very inaccurate. You would need one of the good one's like BeanAnimal and AZ have if you wan't accurate readings. Are they worth the money? Nope! Not unless your a water expert like those dudes

OK, I'm done. You ask for numbers, and when they are given to you, there's no way they can be right.

I'm out.

--Colin

 

[AZDesertRat]

For accurate TDS readings the inlines are not accurate due to not being temperature compensated. If you look at the probe, there is a fatter part and it has a small square hole in it, this hole is where the temp sensor resides so they are reading air temperature and not water temperature. Unless your air and water are exactly the same it can be significantly off. I own two of them and use them as guides only, I rely on the HM Digital COM-100 handheld for accurate readings.
A TDS of 6 down from 500+ is realistic. I get 6.2 to 6.4 down from about 850 so it can be done. Thats actually a pretty good number compared to what most people get.

 

[BeanAnimal]

I guess this is the time to warn people of "full scale accuracy" and how really bad most of our meters are

Take a hanna TDS-1 It is 0-999 TDS at +/- 2% full scale.

That means it can be off by +/- 20 PPM when properly calibrated.

Now is that 0 TDS water really "0 TDS" and what is the REAL output of the membrane in question?

Robby, I do not have a precision meter. I had HAD a decent one... They tend not to work well after a 1 gallon can of corrosives eats through it's container leaks into their storage box. Sadly, it and a few other high end items that I secured from a bankruptcy sale were damaged by my stupidity (Also KIA were a nice FLUKE 45 bench meter and a fluke handheld storage scope and an assortment of other goodies). Easy come easy go I suppose.

 

[rubikcube]

<a href=showthread.php?s=&postid=9750892#post9750892 target=_blank>Originally posted</a> by BeanAnimal
Lets look at just doing DI with no RO:

25 PPM into the max cap system will yeild 1800 GALLONS of water. That is $99 for the base DI unit and 2 MaxCap refills at $35 = $99 + $75 = $174 dollars. If all purchased from spectrapure.

25 PPM into a standard 5000ppm capacity cartridge would yield 200 gallons of water. So that is 9 total DI refills (2 in the initial purchase and 7 refill cartridges @ $12 to get 1800 gallons = $62 + $82 = $142

Now if one were to do as you suggest and replace the MaxCap resin after 1/3 and 2/3 with the $14 filterguys RESIN, then the cost is down to $99+$28 Or $127. Will the filterguys resin protect the Silica Buster DI for 1/3 1/3 and 1/3 to get the capacity out of it? Who knows. It does not sound like it would.

That of course is also assuming that BOTH resins have a capacity of 5000ppm

THE BIG DIFFERENCE HERE IS THE FACT THAT THE OUTPUT IS NOT THE SAME. The maxcap should put out cleaner water. Is it worth paying the extra for? That is up to you. Remember 0 tds is not the end all beat all target for some people.

It's not like I'm just making this stuff up:

http://www.spectrapure.com/St_MaxCap_p0.htm

My numbers aren't wrong and THE OUTPUT IS THE SAME. I calculated thefilterguys' portion of that using their semiconductor grade resin. Don't tell me it isn't the same until you can actually show me the test results. I'm guessing you can't.