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Need info On Reverse Osmosis

Old 06-05-2007, 08:32 AM
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Default Need info On Reverse Osmosis

Does anyone know much about RO systems? I'm talking about the kind that mount under the sink with a single tap, not a whole house one. I had a plumber install one at my last house and want to get one for this house. Mighty expensive though. So Home Depot has a GE one for about 1/3 of the price. 2.5 gallon tank, 10 gallons per day. It only has 2 RO filters and a carbon filter where the last one I had had 3 RO filtersand a carbon filter. Comes with a data sheet that says it removes 98% of this and 98.4% of that etc. but who can tell me what I should look for in this type system?

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Old 06-05-2007, 02:43 PM
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My understanding is that most of the systems "throw away" water at a pretty high ratio. IE to make 5 gallons of RO you "throw away" 30 gallons of dirty water. However, I've recently seen one or two systems somewhere (HD/Lowes/maybe Costco?) that claimed not to throw ANY water away. Not sure if those have the same storage tanks etc?
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Old 06-05-2007, 03:13 PM
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Default RE: Need info On Reverse Osmosis

thresher15 - 6/5/2007 8:32 AM

Does anyone know much about RO systems? I'm talking about the kind that mount under the sink with a single tap, not a whole house one. I had a plumber install one at my last house and want to get one for this house. Mighty expensive though. So Home Depot has a GE one for about 1/3 of the price. 2.5 gallon tank, 10 gallons per day. It only has 2 RO filters and a carbon filter where the last one I had had 3 RO filtersand a carbon filter. Comes with a data sheet that says it removes 98% of this and 98.4% of that etc. but who can tell me what I should look for in this type system?

I have a 200 gallon aquarium that I do RO/DI water changes of about 55 gallons a week. Since you don't need the de-ionization stage for drinking water (makes water taste funny/dry) you can get by with just about any RO unit. The magic is in the membrane, only nearly pure water will pass through the membrane, the rest gets discharged down the drain. Prior to the this membrane the filter will usually have a sediment filter (usually 1 micron) which removes large particles, then it goes through a charcoal filter. The charcoal filter removes much of the clorine present prior to going through the membrane. All the water that gets past the membrane will collect in your your drinking water tank. How much pure water a day do you need to make is the real question. The membranes determine how much water a day you make. My aquarium RO/DI unit (Kent Marine) can make 100 gallons a day. (my water is collected in a sump below my tank and takes about half a day to fill up) For drinking water you can use a much more inexpensive 10 or 20 gallons a day membrane. Membranes need to be replaced every x amount of gallons, your membrane packaging will say how often to replace. The sediment and charcoal filters also need to be replaced at certain schedules. My unit cost about $400.00 and the yearly filter replacements cost about another $200. I've seen the drinking water filters at Lowes and Home Depot for much less. I think most of the drinking water tanks are 3-5 gallons. Installation is very simple, but water leaks and water damage can be quite expensive. You might want a plumber to install.
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Old 06-05-2007, 03:32 PM
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Yes, they only recover from 10-20% and the rest will go into my septic tank. The accumulator tank will hold a useable 2.5 gallons. We have a well by the way. The one I bought will make up 10 gallons per day which was enough in my last house. We just want it for drinking water, ice maker and cooking. It gives my wife the warm and fuzzies knowing the water is "clean", you know what I mean?

Just wondering how a unit with 2 filters compares to the one I used to have that had 3? My guess is that the unit with 3 filters probably had a sediment filter and therefore the RO filter lasted longer/was more efficient.

Lud, 100 gallons per day is a lot, no?

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Old 06-05-2007, 03:56 PM
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They do make multiple membrane filters, but they are not very common. A single membrane should be fine for your drinking water application. The other "filters" are "PRE" filters for the membrane itself. The pre filters will make your membrane last much longer...and at about $100.00 a pop for some of the high end membranes, the $25.00 prefilters make sense.

Yes a 100 gpd is alot. Sometimes I do 100 gallons a week for the water changes, usually on the weekend. A 50 gpd wouldn't cut it. Also during the initial fill of the tank it would have taken four days or so to make that much water.

Some people use the waste water for gardens or watering the plants, generally it takes about 100 gallons of tap to make about 25-30 gallons of pure filtered water.
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Old 06-05-2007, 05:58 PM
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Default Re: Need info On Reverse Osmosis

I deal with well water treatment systems quite a bit. Can you give us an idea of what the water quality problem is that you're trying to correct? There may be other (better) options for you.
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Old 06-05-2007, 08:30 PM
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supposedly pouring a gallon of clorox down a well has good results... probably aint drinkable fora while though, but its bacteria free!!!
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Old 06-05-2007, 11:46 PM
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Default Re: Need info On Reverse Osmosis

Don't know much about reverse osmosis but, I was an expert on reverse paristalsis during my freshman year in college.
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Old 06-06-2007, 08:30 AM
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Hydro,
The well has not been drilled yet but nitrates are the big offender in this area. When we bought our last house we could not get a loan from the bank untill we had the RO installed due to nitrates. My question is just whether there are significant differences between the consumer brands. Some of them have more filters than others. I figure the extra filter is a pre filter and will help the RO filter last longer?
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Old 06-06-2007, 09:12 PM
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Default Re: Need info On Reverse Osmosis

Nitrates usually occur as a result of former agricultural operations, therefore nitrates are more prevalent in shallow aquifers. One thing i would recommend is getting the best well contractor in your area to install the well and not spare any expense here. It will very likely save you money in the long run. Make sure they grout the well properly and consider paying more for a well screened in a deeper aquifer that should be less likely to be contaminated.

RO systems will work OK for nitrates, but some ion-exchange systems may work better and be cheaper to operate and maintain. The technology for RO systems has improved quite a bit in the past few years, but so has other types of water treatment, such as ion exchange. One caveat with ion-exchange systems is to make sure you don't put the backwash water in your septic system; sometimes that can cause septic systems to fail prematurely.

If you still need a water treatment system, make sure its installed and maintained properly by a reputable firm. Make sure you sample the influent and effluent regularly to make sure that the system is working properly. Don't let them get away with sampling the system just once right after its installed. Very few states regulate water treatment companies, and sometimes they get away with some stuff that is ineffective or possibly even dangerous. A good source of local information for you should be the county health department and/or agricultural extension service. Hope this helps.
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Old 06-06-2007, 09:56 PM
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Default RE: Need info On Reverse Osmosis

Call Pumps, Inc in Bear, DE for a reccomendation on well driller and equipment for your system. These guys deal with the best people and equipment.
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Old 06-06-2007, 10:39 PM
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It's the opposite of foward osmossis!

Sorry I'm such a wise a**mossis!
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