RO/DI Unit questions

[rwhite]

I am considering purchasing an RO/DI unit, but was curious about the cost effectiveness of the system. I figured this would be the best place to get some info. Background: We have been using the Aq. Pharm. filter unit for just over a year now and seems to be producing "clean" water for us. We've never tested for TDS before or after, so I'm not sure of any of those #s. We get replacement cartridges for about $20 and one will produce approx. 50g of water. After doing some figuring with a price set for an RO/DI from this site, we calculated about 550g for the price of the unit.
The question is: How much water will an RO/DI produce? The only info given is amt per day, but not for how many days. I'm assuming that the filters need to be changed at some point. And I'm pretty sure it depends on how "bad" the water is to start with. There are no "replacement filter" prices, so that is also a concern.
Any kind of info would be appreciated and any questions gladly answered if I can. Thanks again.

 

[blk822]

I purchased a water general on e bay for $100. And it produces water at 4 ppm tds. Its a 6 stage unit and is supposed to produce 110 gpd , but I now it only puts out about 40 gal in a 14 hour period. I have used mine now for 4 months and its still at 4ppm tds. I am very happy with it. and for the price I can't beat it. I guess the company sells the filters as a set for about $30, and they say they should last about a year.

 

[mobikobeyob]

Mine is a 75 gpd unit, and the manufacturer says with average water quality you should change the filters out every 6 mos. or so. I figure 75gpd X 6 mos. thats a lot of water. so if i use 2 gpd thats like forever. lol I got a TDS of 1 with the first 55 gallons I ran through it.
The R.O. membrane is good for 1 year. and a set of replacement filters is about 15.00. plus the D.I. cartridge which is like 15.00 also. basically if I made 75 gpd for a year it would cost me like 150.00 plus the water bill. well worth it if you ask me. those tap water filters can cost a heap to maintain.
Hope this helps,
Mobi

 

[zanemoseley]

if you have to replace the filters once every 6 months than you don't have very good filters, good filters should be good for about a year, RO membranes should be good for at least 3-4 years, I have a Typhoon III RO/DI from airwaterice.com

 

[zanemoseley]

man I read you post again and its even more messed up than I thought, if the manufacturer says you have a 75GPD unit thats just how fast it can make water, They're not assuming you're actually gonna make 75GPD and the filters should be rated most of the time by how much water you make now how long you have them. The GPD is ALWAYS rated by the RO membrane, 75GPD membranes filter out more solids than a 100GPD unit which sends a lower quality water to the DI cartrige which will allow you to make water quicker but will also wear out your DI cartrige sooner.

 

[rwhite]

Yes, that is also a very good point. If I made say 75g a day, thats way more than I have in tank water, we just have a 55 and 10. Let assume I'm doing at least a 10% change every 2-3 weeks, thats like 15-20 gallons or so and of course top off. So, a unit that produces a smaller amt per day would be better for my needs and given that rate coupled with say 25g a day and amt of changes(every 2 wks) it would produce approx. 650 gallons a year (assuming the filters were changed after 6 mos. and ready to change the membrane after the year is up). Is that where the cost effectiveness would apply? A one time price for the unit itself and thereafter change the filters twice lets say a year to be on the safe side or only once as zane has said. Like I said I'm just using #s from this site, I'm sure I can find a cheaper unit.
Am I making sense?

 

[mobikobeyob]

yeah, you got it. I am soooo glad i got mine. I just go out to the garage and turn the valve on my reservoir, and fill up my topoff bucket, then the RODI kicks on and replenishes my reservoir for the next use. that way I have plenty of water on hand for an emergency. and never have to leave the house.
Mobi
here are some pics -->

 

[mobikobeyob]

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[mobikobeyob]

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[fishman622]

Originally posted by blk822
I purchased a water general on e bay for $100. And it produces water at 4 ppm tds. Its a 6 stage unit and is supposed to produce 110 gpd , but I now it only puts out about 40 gal in a 14 hour period. I have used mine now for 4 months and its still at 4ppm tds. I am very happy with it. and for the price I can't beat it. I guess the company sells the filters as a set for about $30, and they say they should last about a year.
i have the same one it very fast, do you have a pressure booster, if not get one. it will produce more water in a day. :happy:
drew

 

[rwhite]

Cool...nice pics too. Guess that would have to be the thing to figure out, where to place the system. My other question would be, how mobile are they once they're hooked up? As of now we're just renting and NOT looking forward to any kind of move, but its enevitable.
Anybody else got any info to share?