I am thinking about getting a RO(DI) unit for water purification and was looking out for experiences you have with such a unit. I am unsure of what to get at this point, but unit should be able to produce water with 0ppm (or very close to that), and it should produce a fair amount of water in a short time, lets say about 20gal in 2-3 hours. Not sure if that is reasonable. I like to move to storage once I have enough water as I have no space for a permanent installation.
So, my questions to you are:
What system are you using with Ottawa city water?
How low is the TDS [ppm] of your RO water?
And how many gallon does it produce per hour?
Also, do you think that DI is necessary to get very low TDS with our water?
Thanks for you input!
You can ALMOST get to 20gal in 3 hours with a 150GPD unit. Any RO/DI unit worth buying will give you 0 TDS out.
I use the BulkReefSupply 5 stage Chloramine Plus system. I get 0 TDS out. I get about 3gal/hour. TDS between the RO and the DI is in the low-mid 30s.
I'm not sure of my brand name. But I wanted to ad that water pressure and temp have a lot to do with the effective TDS and the production rate. Or so I'm told. I run about 25feet of tubing into my sump to warm the water a bit before hitting the Ro/di.
IIRC it's "the colder the better" for RO efficiency.
i was going to say that too!
Quote from: bt on January 04, 2012, 05:13:36 PM
IIRC it's "the colder the better" for RO efficiency.
Geesh! I hope others chime in and settle the cold/warm issue. I might be doing it all wrong.
Wouldn't be the first time. Or likely last lol
Quote from: fischkopp on January 04, 2012, 04:09:10 PM
I am thinking about getting a RO(DI) unit for water purification and was looking out for experiences you have with such a unit. I am unsure of what to get at this point, but unit should be able to produce water with 0ppm (or very close to that), and it should produce a fair amount of water in a short time, lets say about 20gal in 2-3 hours. Not sure if that is reasonable. I like to move to storage once I have enough water as I have no space for a permanent installation.
So, my questions to you are:
What system are you using with Ottawa city water?
How low is the TDS [ppm] of your RO water?
And how many gallon does it produce per hour?
Also, do you think that DI is necessary to get very low TDS with our water?
Thanks for you input!
aqua vision 75, got it from Ray
ro= 8 tds
di= o tds
75 gal per day it is rated for
yes di is necessary to get 0 tds, may depend on incoming tds though
I'll see if I can dig up the source of colder=faster.
Quote from: Hookup on January 04, 2012, 05:18:10 PM
Geesh! I hope others chime in and settle the cold/warm issue. I might be doing it all wrong.
Wouldn't be the first time. Or likely last lol
i think the benefit of warmer water is that the pressure is higher wich
is good, but colder water holds less :impurities"
i could also have the wrong info haha
While we're digging up research info. Here is a related question
How come tap water doesn't have copper in houses that are all copper plumbing? I'd think trace amounts would build up over months if not years then.
Quote from: Hookup on January 04, 2012, 05:39:57 PM
While we're digging up research info. Here is a related question
How come tap water doesn't have copper in houses that are all copper plumbing? I'd think trace amounts would build up over months if not years then.
i think your right if the water sat in the pipe for months/years, but it is usually flowing through the pipe.
Quote from: bt on January 04, 2012, 05:13:36 PM
IIRC it's "the colder the better" for RO efficiency.
I believe that it's actually the opposite. Warmer water is more effecient. I'm not sure why and can't find the link anymore that explains it. With my 75GPD unit, there is a significant drop in production in the winter.
For Fischkopp, you'd want to look at a "Chloramine" unit, or at the very least, a unit that has 2 carbon stages. As you likely already know, Ottawa uses chloramines rather than chorine. Chloramine is a mixture of ammonia and chlorine. If it all doesn't get stripped away before the RO membrane, the chlorine will have a tendency to greatly reduce the life of the membrane.
I remember when setting up my Aquasafe RO/DI that the instructions clearly indicated NOT to run warm water through it because it degrades the membrane faster. I don't think there was any more information on it than that, really. Mine is just hooked into the cold water line at a wash basin, and into a 30G tank with a heater and powerhead.
When I have time, I plan on running a line directly to my sump compartment where a 5G bucket lives, and throw a heater in there - and my Tunze 3155 space Osmolator takes care of my top up.
Oh, and as for the RO/DI unit, Aquasafe works well - but you'll want to swap the 5 micron carbon filter with 1 micron to remove chloromine. I get 100GPD out of it, at 0 tds...
Quote from: Rybren on January 04, 2012, 06:12:00 PMFor Fischkopp, you'd want to look at a "Chloramine" unit, or at the very least, a unit that has 2 carbon stages.
It's not enough to have 2 carbon stages, it's also the size rating of the carbon stages. IIRC, you need the second carbon stage to be rated for 1 micron to properly deal with Chloramine.
In my understanding that to be truely effective in removing CHLORAMINES from thr the water it is the type of carbon and the most popular used method is a sediment filter,activativated carbon filter then CATALYTIC carbon(which is the one for chloramines)
RO membrane then your DI
Ray
+1 to Ray. I do not belive that the pore size is relevant to CHrolamine removal (but I could be wrong)
Here's a link to an article by Randy Holmes-Farley on Chloramine.
http://reefkeeping.com/issues/2003-11/rhf/feature/ (http://reefkeeping.com/issues/2003-11/rhf/feature/)
For those who don't want to read the entire thing, here's the down and dirty...
Lessons Learned and Suggestions:
1. Most RO/DI systems seem capable of removing chloramine adequately for aquarists.
2. The carbon cartridge may become less useful over time, and it is possible that the chloramine removal effectiveness of a system may be lost before the DI appears to need changing.
3. Cheap sediment cartridges may expose the carbon cartridge to unnecessary fouling, which may permit chloramine to pass through the system. Cartridges should be replaced as soon as the pressure drops significantly, even if RO/DI water is still being produced at a reasonable rate or purity as measured by total dissolved solids.
4. Testing for chlorine and chloramine is easy, so any concern is easily reconciled.
Thanks everyone for their input!
It looks like getting the TDS down to 0ppm isn't a a problem if the RO unit has DI. That's good!
I read a bit up about the cold/hot water issue. With increasing temperature, the holes in the membrane will expand, allowing more water to pass through. But the bigger holes also allow more impurities to pass. Hot water is said to damage the membrane. For best RO water it's recommended to use cold water.
I didn't think about chloramine. Do you trust your RO/DI to remove it or do you still add a bit of prime to be on the safe side?
I trust mine, but I also made sure to get one with the right carbon stages to handle it.
I also trust my unit to remove all of the chloramine.
whats the city's water TDS without treatment? what is the phosphate and nitrate level?
Take a look at the Detailed 2010 Britannia Purification Plan Drinking Water Quality summary:
http://www.ottawa.ca/env_water/water_sewer/water_wells/wells/city_wells/britannia_en.html
Conductivity is 159us; that will translate to 80 ppm on most TDS testers.
Yup, the last time I checked my tap water it was 85.
Quote from: fischkopp on January 05, 2012, 02:46:55 PM
Thanks everyone for their input!
It looks like getting the TDS down to 0ppm isn't a a problem if the RO unit has DI. That's good!
I read a bit up about the cold/hot water issue. With increasing temperature, the holes in the membrane will expand, allowing more water to pass through. But the bigger holes also allow more impurities to pass. Hot water is said to damage the membrane. For best RO water it's recommended to use cold water.
I didn't think about chloramine. Do you trust your RO/DI to remove it or do you still add a bit of prime to be on the safe side?
Id like to see that information if you can post it please. I think defining hot and cold is an issue that first needs to be cleared up. there's a difference between 70degrees and 100degrees... HOT water is likely bad and it would hold higher TDS due to the excited state of the water... and i can see it expanding the membrane... but 70* is not really hot water, it's just not cold...
i can see how cold water, like 40* water would shrink holes in the membrane and create a significant waste to clean water ratio increase under the same principal that hot will allow more tds thru the membrane.
I wish I could say this is why I believe that 65-70degrees is the optimum temp for the water, but really its just some rumor I picked up along the way... :)
I was jnformed that membranes when rated are measured at approx 60 PSI and 70 degree F water temp.So if yoiu are looking for optimal output according to membrane output these are the numbers you wish to have.
Ray
Quote from: Hookup on January 05, 2012, 05:53:19 PM
Id like to see that information if you can post it please.
It's from a German site: http://www.drta-archiv.de/wiki/pmwiki.php/TechnikOsmose/Wassertemperatur
It sounds like in the end it pretty much depends on the quality of the membrane. I wouldn't be surprises if the membranes that we get today are less susceptible to temperature differences, whereas a decade ago these rumors were actually true.
Perhaps, but there is a vastly different level of performance in my system in the summer versus the winter. Production really drops in the winter.
From the Alberta Government website:
Temperature
The optimum water temperature for most reverse osmosis membranes is 25°C. As the temperature drops to 5°C the capacity of the reverse osmosis unit will be reduced to less than one half. Long, small-diameter water feed lines will allow the water to warm up to room temperature (20°C) before reaching the membrane. This will increase treated water production.
Here's the whole article...
http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex5432 (http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex5432)
Quote from: ray on January 05, 2012, 06:16:01 PM
I was jnformed that membranes when rated are measured at approx 60 PSI and 70 degree F water temp.So if yoiu are looking for optimal output according to membrane output these are the numbers you wish to have.
Ray
This is spot on with what I believe to be true, but I got nothing other than a quote from Ray to back it up. But really, who needs more than that? Thanks Ray! Lol
Quote from: Hookup on January 04, 2012, 05:39:57 PM
While we're digging up research info. Here is a related question
How come tap water doesn't have copper in houses that are all copper plumbing? I'd think trace amounts would build up over months if not years then.
The reason that there aren't trace amounts of copper is that the tap water isn't acidic enough to cause the degradation of the copper pipe. If provide enough time, a month (just a guestimate), you would most likely find trace amounts of copper in the initial bit of water coming out of the pipe, but after a few minutes this would clear. The lead solder once used followed the same situation, except that it is more reactive and thus degrades/leaches faster, overnight non-use and you would find trace amounts.