Ro Di filters

[brownguy]

does anyone know in what order do the filters go ? I have a kent maxxima rodi unit ?

 

[james s_]

It goes from the higher Micron to the smallest. The Smallest being the last filter before it goes out to your DI.

 

[buckeye field supply]

46bfinga;232731 wrote: It goes from the higher Micron to the smallest. The Smallest being the last filter before it goes out to your DI.

That is one scholl of thought - the biggest supporter of which was a now retired vendor in Florida.

A better approach, in our opinion, is that you should use SEDIMENT FILTERS (only) in that sort of order - for instance, a 10 mic, followed by a 5 mic, followed by a 1 mic - if you have multiple sediment filters. Sometimes we use these sorts of configurations with systems run on well water with heavy sediment loads.

Once you get to the next filter type however (the carbon block), that line of thinking doesn't apply any longer. If for instance your last sediment filter stage was a 5 mic, you would not want to follow that with a 1 mic carbon block. If you did, the carbon block would act as a sediment filter. The sediment trapped in the carbon block will cause it to clog too soon, and will not let the carbon do the job it is intended for - removing VOC's (especially chlorine).

Russ

 

[buckeye field supply]

To answer the original question, generically, the order should be:
sediment filter -> carbon block -> RO membrane -> DI resin

Russ

 

[james s_]

Hmm that's interesting Russ,

My 2 RO/DI's are a Air,water,and Ice and a Filter guys unit, and I'm pretty sure that is how they are done??? It amazes me how different companies have different opinions on the same exact process. My filters have lasted me a long time. Im about to change out my filters on both units and you have me second guessing which order I should put them in.

Here is the layout of my Air,Water,and Ice:

1. 10 Micron Sediment
2. 5 Micron Carbon
3. 1 Micron Carbon
4. Filmtec Membrane
5. DI

And my Filter Guys Unit:

1. 5 micron poly sediment filter
2. 5 Micron Matrikx NSF rated CTO/2 carbon block filter
3. 0.6 Micron Matrikx NSF rated +1Chlorine Guzzler carbon block
4. RO membrane 75 GPD Dow FilmTec
5. DI

 

[james s_]

Here is a little quote from the guy's over at Air,Water ,and Ice about the filters...

Recommended Filter Array

The idea behind an array of filters is to provide for optimum pressure and a long filter life. The pre-filter micron rating required to optimize the life of a reverse osmosis membrane is five micron. No manufacturer asks for more protection than that and nothing is gained by smaller micron filters. In fact, you only hurt the overall performance of the system by using smaller micron filters. How do you hurt it? By causing excessive pressure drop.

Never install a one half (0.5) micron filter as a pre-filter. A filter array is designed so that each filter does the work required of it and protects the next filter in line. It would make no sense to dump big particles of dirt on a fine filter. You would clog it up immediately causing a great deal of pressure loss.

What I now recommend is: Get a ten micron sediment filter for your first stage, no smaller! Then obtain a good quality five micron carbon block, acid washed filter for the second stage. The ten micron filter has removed all of the dirt and sediment over ten microns from the water which protects the five micron filter. Now, all the five micron filter has to remove is sediment between 5 and 10 micron. In the third stage get a quality one micron carbon filter or a sediment filter if you have well water. You have now accomplished filtration down to one micron, five times the manufactures requirements. You have not lost a great deal of pressure and the filter can now provide you full service. So to recap; the ten protects the five, the five protects the one, and the one micron exceeds the requirement to protect the membrane by a factor of five, so your membrane sees only one micron sediment... one fifth the requirement.

Protected by a 10-to-1 micron array, the membrane is free to go about the task of removing bacteria, virus, salt, ions and dissolved metals (TDS). The filters alone have no impact on the TDS and should never be relied on to remove bacteria. Ions and bacteria are best left to the membrane. After the work done by the pre-filters and membrane, your water is very pure. The final stage is DI -- A typical mixed bed DI cartridge is capable of reducing the TDS to zero (0).

It kills me to see anyone recommend a one micron filter for the first stage!

The H2O Guru's at Air Water & Ice

 

[buckeye field supply]

That write up from AWI harkens back to Walter - the vendor who sold AWI to the current owner.

Not sure where the other vendor is coming from.

Bottomline - let your sediment filter(s) do the job of trapping sediment, and let the carbon do the job of removing VOC's. That's what they are designed for. If you ask a carbon block to do the job of a sediment filter, it will, but at the expense of what you really should want the carbon block to do.

Russ