RO/DI Units

[wingmans10]

I am on the market for my 1st RO/DI unit but really don’t know what to look for in one. Will a properly operating unit filter out EVERYTHING that the city puts in the water? I may be talking out of school, but I remember hearing about a year ago of the city putting fluoride in the water? I am tired of the endless trips to the local store to buy distilled water by the gallon. Is there a life expectancy on the filters and if so, how is it determined? Thanks in advance.

 

[zachluhrs]

Many different Towns and Cities put a variety of things in their water depending on the quality of their source water and their location. A good RO/DI unit will filter out 99.9% of contaminants. A great RO/DI unit will have double DI cartridges after the RO. The company AquaFX makes great quality RO/DI units. Their "Mako" unit is a 5 stage unit with double DI's. All cartridges and membranes are from DOW Chemical, their units have IN/OUT TDS monitors, and a pressure gauge is included.
The life expectancy on the filters will depend on how much water your going to be producing weekly or monthly, on the quality of your source water, and on the Gallon Per Day unit you choose. I take it your going to be making water for your 24g Nano, doing water changes monthly, and topoff weekly. Depending on the RO/DI Gallon Per Day unit you choose, I would change the sediment and carbon once a year. The DI's would probably need changing every 1.5-2 years. The RO membrane roughly every 2 years. Again, filter replacement will depend on the quality of your source water, how much water you will be making monthly, and on the GPD unit you choose. If you choose a unit that will produce RO/DI quickly, for instance 100GPD, then your RO Membrane wouldn't need changing as often, given your specific needs. Hope this puts things into perspective for you.

 

[wingmans10]

It does, thatnk you for the info. On a monthly basis, I would estimate I go thru 20G for salt water and roughly another 10G for top off in a month. That is doing weekly water changes and daily top offs.

 

[AZDesertRat]

Prefilters and carbon blocks should be changed out every 6 months regardless of usage as a precaution against bacteria and virus growth inside the housings and filters. A good RO membrane if it is used along with high quality pre and carbon filters which have been maintained properly should easily exceed 3 years of normal use if not more. DI resin is entirely dependent on the quality of the water leaving the RO membrane and how much water you make, you cannot put a timeframe on it.
If you are just looking I would recommend avoiding the e-bay units for the most part, they are not the same quality as those sold by sponsors and vendors here on RC and will not give you either the filter life nor water quality you should expect.
Four vendors that are also sponsors of RC are:
www.spectrapure.com
www.buckeyefieldsupply.com
www.thefilterguys.biz
www.purelyh2o.com
And yes with a good quality RO/DI you can expect water that is 99.99% pure or what is considered semiconductor grade water.
I use the RO portion of mine fro drinking water and icemaker as well as to feed the DI and aquarium water so it receives lots of use.

 

[wingmans10]

Is the "CHLORAMINE FILTER" a recomended upgrade with these units and if so, what purpose do they serve? Remove more imperfections? Just a brand name? Just trying to determine what unit will best serve my needs now and in the future.

 

[AZDesertRat]

Instead of using chlorine as a residual disinfectant some utilities choose to use chloramines. You need to know if your utilility does or not. You can call and ask for a copy of the annual water quality report and it should be listed there if not just ask them if they use chloramines.
Chloramine filters are only necessary if they use chloramines and if you are not using 0.6 micron carbon block which serves the same purpose. If you do use a catalytic carbon chloramine cartridge follow it up with a final 0.5 micron sediment filter to trap the fine dust from the granular media so it does not pass through to the membrane and shorten its life. Myself I would just use the good 0.6 micron carbon block and forget the granular media all together, it works just as well if not better.