RO/DI unit?

[rmiga13]

Can someone tell me what they think about this unit?
Is it any good or should I pass up on this?



http://cgi.ebay.com/New-Reef-6st-100GPD-Reverse-Osmosis-RO-DI-Water-Filters_W0QQitemZ120165767727QQihZ002QQcategoryZ20684QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

[jdieck]

No good.

[rmiga13]

Why?

[Piscator]

I bought mine from ebay. Wouldn't do it again. My next unit will come from a reputable reef tank supplier that has a dedicated customer service department. Any of the RC sponsors would be a good choice. I would gladly pay double the ebay price to get experienced customer service folks and a good aquarium reputation. I'm not knocking that particular unit, but I've learned that there are many things you can do with these RO/DI units and having knowledgable folks to talk to is worth a little extra $$.

[Duff Man]

I have one and am happy for the most part. I get about a 98% rejection rate from the RO(650 TDS in, 10-15 out). If I had it to do over again, I would get one with a 10" vertical DI cartridge though, and I don't think they offer one. I did hang mine vertically with some success, but they were exhausted too soon.

[Duff Man]

I should say that I did add on a vertical cartridge after the fact.

[Reefer07]

I would never buy any type of equipment off of ebay..filters, heaters, etc. Go to like http://www.thefilterguys.biz/ro_di_systems.htm
and check out their RO units.

[kau_cinta_ku]

if you want a good rodi unit from ebay i sugest this one.

http://cgi.ebay.com/Reverse-Osmosis-Automated-Aquarium-RO-DI-system-NEW_W0QQitemZ250169339109QQihZ015QQcategoryZ46310QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

[marcsmith73]

Same here. Bought an ebay unit, and it was not the best.

I just purchased a Aqua FX Mako from aquatichouse.com.

Hope it does a better job.

IMO This is an area that you can't skim by in. This piece of equipment is very vital.

Good luck.

~Marc

[jdieck]

Mebrane has a rejection of 90% that means it passes 10 % of the impurities which in turn will exaust the DI resin very very quickly.
A 75 gal Filmtec membrane has 98 to 99% rejection so DI cartridges will last 5 to 10 times longer.

Horizontal small DI cartridge is prone to channeling. Vertical 10" DI cartridges are preferred for our application.

GAC polishing filter does nothing for theaquarium water.

5 micron filter will not prevent the 1 micron carbon block to get plugged shortening it's life

Transparent filter housing is preferred to be able to see the media and retained dirt, helps to ID when to change sediment filter.

Output water purity should give no detectable TDS for other impurities like Nitrates, phosphates or silicates to be within acceptable ranges, the one advertized for this unit of 1 to 3 ppm TDS will only last for about 50 to 100 gallons as is, after that the DI will exaust and the output will increase to 30 ppm.

Finally service from these company seems sketchy.

You will be a lot better off spending in a good reliable unit.
Look at www.filterguys.biz www.spectrapure.com or www.buckeyesupply.com

[Lotus99]

I gotta say, the shipping on the unit linked above is really high! $32.50, plus $5 insurance... yikes.

As water is the foundation of your system, it's well worth getting a really good piece of equipment. As others have said, the sponsors have great stuff, and excellent customer service.

[rmiga13]

Thanks for your input, im new to the Ro units themselves as for I have been getting my water from the LFS for the last 1 1/2 years and am finally getting tired of lugging it around every week. I knew had to be a catch to that unti being so cheap Thanks again!

[rwblues]

i bought one and it has worked great.

[wachuko]

Very good thread as I am in the process of buying one as well. Great!

[marcsmith73]

What I found when really researching Rodi units. Most companies rebadge the units bought from other companies. It is such a wacky market on RODI units. These companys set you to burn out filters. Put on the wrong flow restricts, and on....on... They want you to spend money. Bottom line. They make more money in replacent pieces then the darn units.

~Marc

[prolx]

Not to hi jack but has anyone tried this one out and if so how well is it ? http://www.melevsreef.com/ro_di.html

[mouscacha]

prolx: Just bought one and love it. Anyone have experience with the unit over a long period?

[AZDesertRat]

In general you will find most e-bay type units are not the same quality as the Reef units you find here on RC. There are a few exceptions but you will find the exceptions are actually these same RC vendors selling under a different name and sometimes for a higher price than we pay here.
Most e-bay units are just OK drinking water systems even. Most are mass produced in China and Taiwan and shipped here literally by the boat load, they are untested and never touched by anyone who even knows what a reef is.
By comparison you will find the units sold here are hand assembled using only high quality parts and filters in their own facilities one at a time. The use things like 98% rejection rate name brand RO membranes not 90% rejection rate or even untested and uncertified non US approved membranes. They use true 10" standard sized vertical 20 oz. DI filters not little horizontal hollow tubes with a few ounces of outdated resin bobbing around in them. These two items alone make the biggest difference in a unit. Add in better quality prefilters and carbon blocks instead or cheap granular activated carbon and you have a much better performing system backed by a vendor that depends on word of mouth in the reefing community so you can bet they will build a good product and stand behind it.

[wachuko]

So what is the recommendation from the folks here on a 100gpd unit??? Just give me a brand and model number... I need to get one very soon...

[AZDesertRat]

First off, You don't want a 100 GPD unit. Most use a 90% efficient nanofilter membrane and not a true 98% efficient 75 GPD Reverse Osmosis membrane. Huge difference.
There are several choices in the $150-$200 range that will work very well for you.
I would look at:
www.buckeyefieldsupply.com - 75 GPD Premium system
www.thefilterguys.biz - 75 GPD Ocean Reef +1
www.purelyh2o.com - 75 GPD Optima Vision, Automated or Professional
www.melevsreef.com - Reefkeeper (This is the exception to the 100 GPD rule, he uses a different brand of membrane than the others and it is almost comparable to a Dow 75GPD.

[wachuko]

<a href=showthread.php?s=&postid=10886331#post10886331 target=_blank>Originally posted</a> by AZDesertRat
First off, You don't want a 100 GPD unit. Most use a 90% efficient nanofilter membrane and not a true 98% efficient 75 GPD Reverse Osmosis membrane. Huge difference.
There are several choices in the $150-$200 range that will work very well for you.
I would look at:
www.buckeyefieldsupply.com - 75 GPD Premium system
www.thefilterguys.biz - 75 GPD Ocean Reef +1
www.purelyh2o.com - 75 GPD Optima Vision, Automated or Professional
www.melevsreef.com - Reefkeeper (This is the exception to the 100 GPD rule, he uses a different brand of membrane than the others and it is almost comparable to a Dow 75GPD.

Thank you. Will decide between those listed and place an order. :)

[prolx]

<a href=showthread.php?s=&postid=10885185#post10885185 target=_blank>Originally posted</a> by mouscacha
prolx: Just bought one and love it. Anyone have experience with the unit over a long period?

Thanks for your input.

Last night I got fed up with looking at everything and ordered one from Filter Guys at 1 in the morning.

[NeveSSL]

Another one to consider is Air Water Ice. They are just as good as all of the others, just not RC sponsors (used to be, but haven't renewed for some reason).

Brandon

[NeveSSL]

Someone needs to do a sticky on RO/DI. :)

Brandon

[kysard1]

I bought a $75 RO on ebay and got 85% rejection rate.

So after reading threads here I bought a Dow Filmtec 75 gpd unit from one of the sponsors. Same 85% reject rate.

So I recommend getting the cheaper unit. A membrane like the Dow only gets high rejection under the right conditions. Just look at the technical data sheet. Some contaminates are below 50% rejection with it.

[kau_cinta_ku]

<a href=showthread.php?s=&postid=10889175#post10889175 target=_blank>Originally posted</a> by kysard1
I bought a $75 RO on ebay and got 85% rejection rate.

So after reading threads here I bought a Dow Filmtec 75 gpd unit from one of the sponsors. Same 85% reject rate.

So I recommend getting the cheaper unit. A membrane like the Dow only gets high rejection under the right conditions. Just look at the technical data sheet. Some contaminates are below 50% rejection with it.

what is your water pressure at?

[kysard1]

42 psi, thats all I can get out of my well.

[jdieck]

<a href=showthread.php?s=&postid=10889175#post10889175 target=_blank>Originally posted</a> by kysard1
I bought a $75 RO on ebay and got 85% rejection rate.

So after reading threads here I bought a Dow Filmtec 75 gpd unit from one of the sponsors. Same 85% reject rate.

So I recommend getting the cheaper unit. A membrane like the Dow only gets high rejection under the right conditions. Just look at the technical data sheet. Some contaminates are below 50% rejection with it.
Could it have been your housing not properly sealing?
If there is no proper sealing around the membrane, impurities will just bypass it.

[AZDesertRat]

I get 99.23% rejection out of a hand tested Dow membrane. There is no reason to settle for less than 96% no matter what your water conditions are. My tap water TDS is 835 by the way and it doesn't get much worse than that. If you are getting 85% you probably have other problems and not the membrane.

[kysard1]

<a href=showthread.php?s=&postid=10889828#post10889828 target=_blank>Originally posted</a> by AZDesertRat
I get 99.23% rejection out of a hand tested Dow membrane. There is no reason to settle for less than 96% no matter what your water conditions are. My tap water TDS is 835 by the way and it doesn't get much worse than that. If you are getting 85% you probably have other problems and not the membrane.

It all depends on what is in your water.

Let me explain how RO membranes are rated. You can't go by the over all number they advertise. Just look at DOW's Data sheet on the 75 GPD membrane. A perfect example is a common well contaiminate : Xylene. Right on Dow's Data sheet Xylene has a reject rate of 38%. The list is full of contaiminates in the low 80's.

Another common well contaiminate in well water from septic tanks is Urea. Dow Filmtech rejection rate : 70%.

Trust me I spec 10,000 GPD RO units for our chemical treatment lines at work.

[AZDesertRat]

But xylene is limited to a few parts per billion in drinking water already so thats not a good example. Also it is removed by the carbon that precedes the membrane so again its not a good example. Remember you are usually starting out with EPA approved drinking water not hazardous waste. Yes all membranes have limitations but the combination of a good membrane, carbon and DI resin will get just about everything.

All volatile organics are removed by the carbon. Urea is nitrates which are removed mostly by the membrane and polished off by good DI resin. You still cannot beat the 75 GPD Dow Filmtec for an off the shelf membrane. The only membrane better is the hand tested Spectrapures like I have. Guaranteed 98+% in writing.


Trust me I am doing start up on my third 2 million gallon per day membrane system now.

[kysard1]

Nah, xylene is allowed up to 10 ppm. At that level I don't think a typical carbon prefilter will last longer than a few weeks.

Who's well meets federal guidelines anyway? its not like wells are regulated.

The Dow membrane has a good rep here, but on some wells the difference is marginal at best.

[AZDesertRat]

Thats why I only use and recommend a 0.5 micron 20,000 gallon carbon block. Crappy GAC or 10 micron blocks last about 300 gallons is all. A 0.5 will last up to 20,000 gallons at 1 ppm of any volatile so at 10 ppm its still good for quite a bit. I am presently testing one for chlorine breakthru right now to see how long it will really go. I have a 0.2 micron absolute rated prefilter in front of it so its only doing its job and not filtering solids too.

[PJsStuff]

$60 ebay unit works great for me.

[chrisjet]

ditto , i get 0 tds from Pur flow rodi off ebay.

[AZDesertRat]

If you ever get the opportunity to test it side by side with a good unit you will understand what I am talking about. There is no comparison.

[PJsStuff]

What 0tds to 0tds? Whats the diff besides price?

[kysard1]

The only advantage is the claim that the DI resin will last a little longer with the expensive unit.

I wasn't that lucky and believe that with difficult groundwater the differences between membranes are small.

[AZDesertRat]

Look at an RO/DI like a tool you will keep for a long time. The cost savings in DI resin and replacement membranes alone will more than offset the additional capital cost up front. You will not get 9+ years out of a $60 unit I don't care how you take care of it. You also will not get over 4 times the resin life either.
If you can't see that then I'm done here.

[PJsStuff]

Funny thing is i went and bought some DI resin from filterguys and it lasted about 60 gallons (about 2 weeks)and was shot. but yet the cheap di resin i get off of ebay lasted a few months. The filterguys think i have high CO2 in my water and thats what caused my resin to not last. But the ebay stuff lasts lol.

[PJsStuff]

I have nothing against the Filterguys by the way. There great people and are really quick at answering questions.