Need info on WaterGeneral RO/DI unit before buying

DamnPepShrimp · 04/09/2007, 09:39 PM

I am buying a slightly used WaterGeneral Mfg. Co. RO/DI unit wednesday locally. It does 100gpd, 6 stage, and has a flush out kit. I tried doing some research and didn't come up with much. It seems like this company mostly deals with drinking water RO/DI units, but seems that it's ok to use for the aquarium. I am getting a good deal on it I think, but just want to make sure it's an ok unit to use. What makes the other units better for the aquarium? The process should be the same right? I see most 100gpd units going for over $250 and this one I am getting for well under a $100, even though it has been used for a few months. Just curious and trying to be caution. Please help because I am going to pick it up wednesday night, thanks.

AquaDiva · 04/10/2007, 07:20 AM

Here ya go

http://cgi.ebay.com/AQUARIUM-2-110GP...QQcmdZViewItem

rubikcube · 04/10/2007, 07:34 AM

I just bought one and it does a pretty decent job. Takes my tap water from 650 to 13 after RO to 0 after DI. I wouldn't buy one used though. They are incredibly cheap on ebay. Don't count on their tech support being very good though.

BlakDuc · 04/10/2007, 08:08 AM

It looks like a pretty nice system for $100. So, if you are buying a used one for $100, you should probably just get a new one.

DamnPepShrimp · 04/10/2007, 08:24 AM

Thanks for the replies. Well I'd have to factor in shipping as well. It comes with a flush out kit, which is extra right? I am buying it for $70 bucks. Why are these models so cheap? I am in dire need of a RO/DI unit, and I am strapped for cash as well. What do you guys think?

AquaDiva · 04/10/2007, 08:46 AM

The thing you need to know is how "spent" the filters are that are in the unit. If it's been sitting idle for awhile, you may have a problem with bacteria growing inside. How much life is left in the DI resin?
If you have to replace all the filters, you will wind up spending more $$ than if you bought new. The RO membrane alone can cost upwards of $45.

rubikcube · 04/10/2007, 09:17 AM

I wouldn't bother with the flush kit. It has no useful purpose.

David Grigor · 04/10/2007, 10:15 AM

Quote:

Originally posted by rubikcube
Takes my tap water from 650 to 13 after RO to 0 after DI. I wouldn't buy one used though.

\

98% rejection rate is really good.

However, most 100gpd membranes are closer to 90%. Which would in this case would put closer to 65 which would exhaust DI 5X faster than the higher rejection %.

You need to ask this question to the seller. What TDS before and after the membrane. Remember just a few % difference will have a significant impact on your ongoing cost for DI.

DamnPepShrimp · 04/10/2007, 01:13 PM

The seller said that it was used for 6-8 gallons a week for a couple of months. Hasn't been used in a month I would say though. How will I know if anything needs to be replaced? He said I should be fine with it for a little while, no need to replace the filters? I don't know what to do, I'd hate to back out now, I supposed to pick up the unit tomorrow.

AquaDiva · 04/10/2007, 01:29 PM

First.... the guy bought the unit with brand new filters for $99 plus shipping.

Open the unit and feel around? Are the canisters slimey? What color is the sediment filter. A little discolored is OK, but if it's a solid color (usually brown) it needs replaced. If one needs replaced, then I'd replace the three. If it's slimey, it needs replaced.

Hmmm apparantly violated some policy with links, so lets say it's $20 from some online dealer

What color is the DI. It should be kinda a blacky/blue/greenish color. If it is light brown/tan it needs replaced. ..

at some online dealer x2 $12

Does he have a TDS meter. Hook it up and see what the TDS is coming out of the RO membrane, not just after the DI.

that'll tell you if you need a new membrane...

From some online dealer.... $45..
(sorry I had links but got smacked down by the RC police)

Now, everything could be good to go and you get a deal and save $50 bucks.. Cool

Or, you could get home and hook it up and find you need to spend another $77 bucks on filters.

Just look it over well......:

rubikcube · 04/10/2007, 02:25 PM

Quote:

Originally posted by David Grigor
\

98% rejection rate is really good.

However, most 100gpd membranes are closer to 90%. Which would in this case would put closer to 65 which would exhaust DI 5X faster than the higher rejection %.

You need to ask this question to the seller. What TDS before and after the membrane. Remember just a few % difference will have a significant impact on your ongoing cost for DI.

Yeah, my unit originally had the 100gpd GE Desal membrane, but it was bad when I got it. I called them up and they sent me a new membraned, but since my TDS was so high, they gave me the 75gpd GE Desal. At first I didn't think it was working well, but that just turned out to be utter stupidity on my part. Now it works great.

I purchased mine from filterdirect on ebay.

BrentN · 04/10/2007, 02:33 PM

I've been using one of these for 2 1/2 yrs, and still getting 0 tds, but my tap is good to start with, 56. I know these are considered "cheapo" units, but I have no complaints. I have not yest replaced any filters. For the extra 30 or 40 bucks, I'd get a new one w/ fresh filters.

DamnPepShrimp · 04/10/2007, 03:16 PM

You guys seem to be talking me out of this pretty good. Hmmmm.... So how often do the filters/membrane need to get replaced? I didn't think they went that bad that quickly! That is insane! I may just hold off on this then, I am hoping to get a lot of live rock anyway and could use the money. We'll see, any other suggestions then? What is a better unit to go with? I don't need a huge gpd unit, but I don't want to be replacing filters all the time. Decisions, decisions... I guess I should just wait, see about this live rock deal, maybe get a better RO/DI unit. Suggestions?

David Grigor · 04/10/2007, 03:28 PM

Well, what are you doing for water now ? are you buying it ? If so, even if not so effecient ro/di unit is going to pay for itself it a very short period of time. Not to mention the quality of life carrying water back and forth gets real old quick.

If $70 is all you can afford right now, I'd be willing to use until exhausted and replace the membrane later because of the instant savings of making your own instead of buying it between now and then. So definately better than nothing if those are your only 2 options.

You can always replace the key components ( mostly membrane, possibily upgrade to 10" DI cannisters if this has the cheapy horizontal ones ) with higher quality down the road and still be a win win vs. buying all your water until then. Sure in the long run it may cost your more than buying a brand new unit but by the time you account for buying your water while you wait you will still have saved.....

DamnPepShrimp · 04/10/2007, 03:39 PM

I am just using tap water with additives to take out the chlorine in it. My fish are all very hardy and I have had my 30g reef set up for over a month with no problems. I have mostly hardy corals, softies mainly. I just wanted a RO/DI unit because I know I will need better water. I saw this one for sale and figured it was a good deal. Upon researching it, finding out I may have to replace $75 worth of filters, screw that. I have a live rock deal that may work out where the money would be better put to use. I could always get an RO/DI unit later, a better one when money is not so tight. I have been getting along fine without one for a year now, no problems. For now, I am just going to pass on the used RO/DI and wait to see how this live rock deal works out. I will wait for a better one to pop up, maybe a new one, or get one from a lfs when they have a sale. Which ones are good, less maintenance and filters lasting the longest? I don't need a huge gpd one, just something that can make my water better with me having to do to much replacing or work on it. Sounds like a used one isn't what I need, better to buy new and not deal with all that. BTW, thanks for the replies and help, from everyone too, I really don't know anything about RO/DI units.

DarG · 04/10/2007, 04:37 PM

David is right on. I had a 75 gpd unit that I replaced a 18 gpd unit with. I went through the DI resin atleast 2x (closer to 3x) as fast compared to the 18 GPD unit. So I went back to the 18 gpd. I don't have any type of automatic on/off system so I have to keep an eye on the water in my 35 gallon resevoir but as long as I do that I don't have any issues running out of water. Only time it was an issue was when switching to a new aquarium. Other than that, I have no need for for 18 gallons a day let alone 75 and I save a signifigant amount of money on DI resin.

Point is, like David pointed out, the lower volume per day RO membranes generally have a higher rejection rate which ultimately saves on the DI resin. So, going with a higher capacity membrane if you dont really need it ends up costing you more money by burning through more DI resin per gallon of water.

purebullet417 · 04/10/2007, 04:40 PM

my uncle has one with the regular 100gpd filters and runs 20 gals a week through it sometimes more for months and his works great brings the tds down from about 100 to 0 after the di

TwistedTiger · 04/10/2007, 05:09 PM

Buy the ebay RO/DI brand new real cheap and then when you need new filters and resin go to the filterguys and upgrade the filters and resin. Also upgrade to the 75 gallon a day membrane and flow restrictor. You will have used the unit for quite some time, 18 months in my case and then have a brand new unit as good quality as some of the much much more expensive units but at half the price. JMO

DarG · 04/10/2007, 05:20 PM

That one on ebay is far better than using tap water. They claim to be using the GE membrane which is a good membrane. There is nothing wrong with the ebay unit and it's a steal for the price. I'd jump on it. Mine was pieced together over time and probably cost me 3X what the ebay unit costs when all was said and done.

mikedege · 04/10/2007, 05:27 PM

just make sure you have them swap out the 100gpd membrane, they will do it for free, just put a note when you buy it. I swapped out to the 75GPD, but less is always better.

good luck, Mike

plummike · 04/10/2007, 06:39 PM

filter replacement costs? bought mine at Lowes it is a Whirlpool unit. I'll never have a problem getting reasonibley priced replacement filters.

DarG · 04/10/2007, 06:57 PM

The sediment and carbon prefilters are pretty standard. A few bucks a piece. Its the RO membrane that costs the most, 50 bucks give or take a few for a good membrane. Then there is the DI media. I think a full size refill of the mixed bed from the filter guys is about 12 bucks.

DamnPepShrimp · 04/10/2007, 07:01 PM

So it seems that the lower gpd units last longer, as far as filter replacement. Which makes sense obviously. I might just get a 24gpd unit through my lfs. They offer good sales, usually %30 off any dry good item, so I could get it for real cheap. Although I just looked through their catalog and couldn't find any 24gpd RO?DI units, they were only RO units. I should get a DI as well correct? The store is www.thatpetplace.com some of you may have heard of it. My live rock deal pulled through, so I definitely can't get anything anytime soon. Anyone suggest a good RO/DI unit for a good price? Other then the one on ebay. I don't want a huge gpd unit, or have to swap anything out later down the road. Something low maintenance, just replace filters when needed. Thanks everyone for the replies and help.

TwistedTiger · 04/11/2007, 08:20 AM

Quote:

Originally posted by DamnPepShrimp
So it seems that the lower gpd units last longer, as far as filter replacement.

No that's not correct, the filters come before the RO membrane and can only process so much water at a certain TDS. What will last longer is your DI resin because the lower gpd units usually have a higher rejection rate but not always.

I have the ebay unit with filters and DI from the filterguys and have had several others. When I needed replacements I called and talked to Fritz at http://www.thefilterguys.biz/ro_di_systems.htm They are more than willing to talk to you and tell you what you need for your city's water. IMO there is no need to pay $200 or more for a system that gives you no better water and no longer filter life than you can get from a less expensive unit.

David Grigor · 04/11/2007, 12:31 PM

If you using tap, at minimum, I'd be running it through some carbon to help get rid of at least some stuff and won't have to deal with any potential chlorine issues.

Here in MN, with high iron content, nitrates and phosphates in the water, it would be suicide trying to run a tank on tap water.......

04/09/2007, 09:39 PM	#1
DamnPepShrimp Moved On Join Date: Nov 2006 Location: Delaware Posts: 5,152	Need info on WaterGeneral RO/DI unit before buying I am buying a slightly used WaterGeneral Mfg. Co. RO/DI unit wednesday locally. It does 100gpd, 6 stage, and has a flush out kit. I tried doing some research and didn't come up with much. It seems like this company mostly deals with drinking water RO/DI units, but seems that it's ok to use for the aquarium. I am getting a good deal on it I think, but just want to make sure it's an ok unit to use. What makes the other units better for the aquarium? The process should be the same right? I see most 100gpd units going for over $250 and this one I am getting for well under a $100, even though it has been used for a few months. Just curious and trying to be caution. Please help because I am going to pick it up wednesday night, thanks.

04/10/2007, 07:20 AM	#2
AquaDiva Registered Member Join Date: Jan 2004 Location: New Hampshire Posts: 273	Here ya go http://cgi.ebay.com/AQUARIUM-2-110GP...QQcmdZViewItem __________________ Linda Current Tank Info: 75 RR LPS, 30gal refugium, 50gal sump, 2x175 MHs,2x110w actinics, ASM G4

04/10/2007, 08:08 AM	#4
BlakDuc Fragger Join Date: Nov 2006 Location: Waldorf, MD Posts: 4,518	It looks like a pretty nice system for $100. So, if you are buying a used one for $100, you should probably just get a new one. __________________ Joe Cude Current Tank Info: IM Fusion 40

04/10/2007, 08:46 AM	#6
AquaDiva Registered Member Join Date: Jan 2004 Location: New Hampshire Posts: 273	The thing you need to know is how "spent" the filters are that are in the unit. If it's been sitting idle for awhile, you may have a problem with bacteria growing inside. How much life is left in the DI resin? If you have to replace all the filters, you will wind up spending more $$ than if you bought new. The RO membrane alone can cost upwards of $45. __________________ Linda Current Tank Info: 75 RR LPS, 30gal refugium, 50gal sump, 2x175 MHs,2x110w actinics, ASM G4

04/10/2007, 01:29 PM	#10
AquaDiva Registered Member Join Date: Jan 2004 Location: New Hampshire Posts: 273	First.... the guy bought the unit with brand new filters for $99 plus shipping. Open the unit and feel around? Are the canisters slimey? What color is the sediment filter. A little discolored is OK, but if it's a solid color (usually brown) it needs replaced. If one needs replaced, then I'd replace the three. If it's slimey, it needs replaced. Hmmm apparantly violated some policy with links, so lets say it's $20 from some online dealer What color is the DI. It should be kinda a blacky/blue/greenish color. If it is light brown/tan it needs replaced. .. at some online dealer x2 $12 Does he have a TDS meter. Hook it up and see what the TDS is coming out of the RO membrane, not just after the DI. that'll tell you if you need a new membrane... From some online dealer.... $45.. (sorry I had links but got smacked down by the RC police) Now, everything could be good to go and you get a deal and save $50 bucks.. Cool Or, you could get home and hook it up and find you need to spend another $77 bucks on filters. Just look it over well......: __________________ Linda Current Tank Info: 75 RR LPS, 30gal refugium, 50gal sump, 2x175 MHs,2x110w actinics, ASM G4

04/10/2007, 07:34 AM	#3
rubikcube Registered Member Join Date: Dec 2006 Location: Lubbock, TX Posts: 49	I just bought one and it does a pretty decent job. Takes my tap water from 650 to 13 after RO to 0 after DI. I wouldn't buy one used though. They are incredibly cheap on ebay. Don't count on their tech support being very good though.

04/10/2007, 08:24 AM	#5
DamnPepShrimp Moved On Join Date: Nov 2006 Location: Delaware Posts: 5,152	Thanks for the replies. Well I'd have to factor in shipping as well. It comes with a flush out kit, which is extra right? I am buying it for $70 bucks. Why are these models so cheap? I am in dire need of a RO/DI unit, and I am strapped for cash as well. What do you guys think?

04/10/2007, 09:17 AM	#7
rubikcube Registered Member Join Date: Dec 2006 Location: Lubbock, TX Posts: 49	I wouldn't bother with the flush kit. It has no useful purpose.

04/10/2007, 01:13 PM	#9
DamnPepShrimp Moved On Join Date: Nov 2006 Location: Delaware Posts: 5,152	The seller said that it was used for 6-8 gallons a week for a couple of months. Hasn't been used in a month I would say though. How will I know if anything needs to be replaced? He said I should be fine with it for a little while, no need to replace the filters? I don't know what to do, I'd hate to back out now, I supposed to pick up the unit tomorrow.

04/10/2007, 02:33 PM	#12
BrentN Registered Member Join Date: Oct 2004 Location: Kelso, WA Posts: 277	I've been using one of these for 2 1/2 yrs, and still getting 0 tds, but my tap is good to start with, 56. I know these are considered "cheapo" units, but I have no complaints. I have not yest replaced any filters. For the extra 30 or 40 bucks, I'd get a new one w/ fresh filters. __________________ -Gravity Powered, Air Cooled- Current Tank Info: 55 aga, 20 gal sump, 4x54 t-5, O.R. 3500 return, liter meter 3, msx 160

04/10/2007, 03:16 PM	#13
DamnPepShrimp Moved On Join Date: Nov 2006 Location: Delaware Posts: 5,152	You guys seem to be talking me out of this pretty good. Hmmmm.... So how often do the filters/membrane need to get replaced? I didn't think they went that bad that quickly! That is insane! I may just hold off on this then, I am hoping to get a lot of live rock anyway and could use the money. We'll see, any other suggestions then? What is a better unit to go with? I don't need a huge gpd unit, but I don't want to be replacing filters all the time. Decisions, decisions... I guess I should just wait, see about this live rock deal, maybe get a better RO/DI unit. Suggestions?

04/10/2007, 03:28 PM	#14
David Grigor Registered Member Join Date: Jan 2000 Location: Brooklyn Center, MN USA Posts: 4,951	Well, what are you doing for water now ? are you buying it ? If so, even if not so effecient ro/di unit is going to pay for itself it a very short period of time. Not to mention the quality of life carrying water back and forth gets real old quick. If $70 is all you can afford right now, I'd be willing to use until exhausted and replace the membrane later because of the instant savings of making your own instead of buying it between now and then. So definately better than nothing if those are your only 2 options. You can always replace the key components ( mostly membrane, possibily upgrade to 10" DI cannisters if this has the cheapy horizontal ones ) with higher quality down the road and still be a win win vs. buying all your water until then. Sure in the long run it may cost your more than buying a brand new unit but by the time you account for buying your water while you wait you will still have saved..... __________________ Neptune Systems 2016 Marine Aquarium Hobbyist of the Year Current Tank Info: 180g mixed reef show tank Last edited by David Grigor; 04/10/2007 at 03:34 PM.

04/10/2007, 03:39 PM	#15
DamnPepShrimp Moved On Join Date: Nov 2006 Location: Delaware Posts: 5,152	I am just using tap water with additives to take out the chlorine in it. My fish are all very hardy and I have had my 30g reef set up for over a month with no problems. I have mostly hardy corals, softies mainly. I just wanted a RO/DI unit because I know I will need better water. I saw this one for sale and figured it was a good deal. Upon researching it, finding out I may have to replace $75 worth of filters, screw that. I have a live rock deal that may work out where the money would be better put to use. I could always get an RO/DI unit later, a better one when money is not so tight. I have been getting along fine without one for a year now, no problems. For now, I am just going to pass on the used RO/DI and wait to see how this live rock deal works out. I will wait for a better one to pop up, maybe a new one, or get one from a lfs when they have a sale. Which ones are good, less maintenance and filters lasting the longest? I don't need a huge gpd one, just something that can make my water better with me having to do to much replacing or work on it. Sounds like a used one isn't what I need, better to buy new and not deal with all that. BTW, thanks for the replies and help, from everyone too, I really don't know anything about RO/DI units.

04/10/2007, 04:37 PM	#16
DarG Registered Member Join Date: Dec 2006 Posts: 5,515	David is right on. I had a 75 gpd unit that I replaced a 18 gpd unit with. I went through the DI resin atleast 2x (closer to 3x) as fast compared to the 18 GPD unit. So I went back to the 18 gpd. I don't have any type of automatic on/off system so I have to keep an eye on the water in my 35 gallon resevoir but as long as I do that I don't have any issues running out of water. Only time it was an issue was when switching to a new aquarium. Other than that, I have no need for for 18 gallons a day let alone 75 and I save a signifigant amount of money on DI resin. Point is, like David pointed out, the lower volume per day RO membranes generally have a higher rejection rate which ultimately saves on the DI resin. So, going with a higher capacity membrane if you dont really need it ends up costing you more money by burning through more DI resin per gallon of water.

04/10/2007, 04:40 PM	#17
purebullet417 Rimless Reef Club Join Date: Jun 2006 Location: long island ny Posts: 1,509	my uncle has one with the regular 100gpd filters and runs 20 gals a week through it sometimes more for months and his works great brings the tds down from about 100 to 0 after the di __________________ My 57 Gallon Rimless Build Thread http://www.reefcentral.com/forums/showthread.php?t=2341582 Current Tank Info: 57 Gallon Rimless

04/10/2007, 05:09 PM	#18
TwistedTiger Moved On Join Date: Apr 2005 Location: B.R. La. Posts: 925	Buy the ebay RO/DI brand new real cheap and then when you need new filters and resin go to the filterguys and upgrade the filters and resin. Also upgrade to the 75 gallon a day membrane and flow restrictor. You will have used the unit for quite some time, 18 months in my case and then have a brand new unit as good quality as some of the much much more expensive units but at half the price. JMO

04/10/2007, 05:20 PM	#19
DarG Registered Member Join Date: Dec 2006 Posts: 5,515	That one on ebay is far better than using tap water. They claim to be using the GE membrane which is a good membrane. There is nothing wrong with the ebay unit and it's a steal for the price. I'd jump on it. Mine was pieced together over time and probably cost me 3X what the ebay unit costs when all was said and done.

04/10/2007, 05:27 PM	#20
mikedege You kidding me or what? Join Date: Dec 2004 Location: the O.C. Posts: 879	just make sure you have them swap out the 100gpd membrane, they will do it for free, just put a note when you buy it. I swapped out to the 75GPD, but less is always better. good luck, Mike

04/10/2007, 06:39 PM	#21
plummike Registered Member Join Date: Jan 2006 Location: near Pittsburgh Posts: 271	filter replacement costs? bought mine at Lowes it is a Whirlpool unit. I'll never have a problem getting reasonibley priced replacement filters.

04/10/2007, 06:57 PM	#22
DarG Registered Member Join Date: Dec 2006 Posts: 5,515	The sediment and carbon prefilters are pretty standard. A few bucks a piece. Its the RO membrane that costs the most, 50 bucks give or take a few for a good membrane. Then there is the DI media. I think a full size refill of the mixed bed from the filter guys is about 12 bucks.

04/10/2007, 07:01 PM	#23
DamnPepShrimp Moved On Join Date: Nov 2006 Location: Delaware Posts: 5,152	So it seems that the lower gpd units last longer, as far as filter replacement. Which makes sense obviously. I might just get a 24gpd unit through my lfs. They offer good sales, usually %30 off any dry good item, so I could get it for real cheap. Although I just looked through their catalog and couldn't find any 24gpd RO?DI units, they were only RO units. I should get a DI as well correct? The store is www.thatpetplace.com some of you may have heard of it. My live rock deal pulled through, so I definitely can't get anything anytime soon. Anyone suggest a good RO/DI unit for a good price? Other then the one on ebay. I don't want a huge gpd unit, or have to swap anything out later down the road. Something low maintenance, just replace filters when needed. Thanks everyone for the replies and help.

04/11/2007, 12:31 PM	#25
David Grigor Registered Member Join Date: Jan 2000 Location: Brooklyn Center, MN USA Posts: 4,951	If you using tap, at minimum, I'd be running it through some carbon to help get rid of at least some stuff and won't have to deal with any potential chlorine issues. Here in MN, with high iron content, nitrates and phosphates in the water, it would be suicide trying to run a tank on tap water....... __________________ Neptune Systems 2016 Marine Aquarium Hobbyist of the Year Current Tank Info: 180g mixed reef show tank