Want to add a 5th stage to my RO/DI, but not sure which.

LeftyReefer

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I recently put in a 4 stage RO/DI system and am loving life not having to lug water around anymore.
Saying that, I recently got another filter housing for free. So I'd like to add it to my RO/DI system to make it a 5 stage RO/DI now.
The problem is that I'm not sure how best to do that.

My water isn't terrible and I already get pretty good life from my filters. I have city water, but it's not too bad. TDS is usually 100 or less.
100 TDS in summer months and seems to drop to 90 TDS in winter months. 60 psi pressure year round. (no pump/booster)

My current filter setup;
Stage #1 5 micron Sediment Filter
Stage #2 5 micron Carbon filter
RO membrane 100GPD
Stage #3 mixed bed color changing DI.

How best can I add/utilize a 5th stage?
Add another sediment filter? Say a 1 micron sediment filter after the 5 micron sediment filter?
Or add another carbon block? I don't currently have issues with CO2 or with chlorine/chloramines, so I'm not sure a second Carbon block would be doing much.
add a second DI cartridge and go with separate anion/cation beds? Add a second mixed bed DI?

Or is adding a 5th stage completely unnecessary?

I already have the housing and I also have several extra sets of replacement sediment and carbon filters that I picked up from Marine Depot liquidation sale.... including 1 micron sediment and carbon filters, and an extra mixed DI cartridge. I just need help determining which setup is best for me.
 

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I recently put in a 4 stage RO/DI system and am loving life not having to lug water around anymore.
Saying that, I recently got another filter housing for free. So I'd like to add it to my RO/DI system to make it a 5 stage RO/DI now.
The problem is that I'm not sure how best to do that.

My water isn't terrible and I already get pretty good life from my filters. I have city water, but it's not too bad. TDS is usually 100 or less.
100 TDS in summer months and seems to drop to 90 TDS in winter months. 60 psi pressure year round. (no pump/booster)

My current filter setup;
Stage #1 5 micron Sediment Filter
Stage #2 5 micron Carbon filter
RO membrane 100GPD
Stage #3 mixed bed color changing DI.

How best can I add/utilize a 5th stage?
Add another sediment filter? Say a 1 micron sediment filter after the 5 micron sediment filter?
Or add another carbon block? I don't currently have issues with CO2 or with chlorine/chloramines, so I'm not sure a second Carbon block would be doing much.
add a second DI cartridge and go with separate anion/cation beds? Add a second mixed bed DI?

Or is adding a 5th stage completely unnecessary?

I already have the housing and I also have several extra sets of replacement sediment and carbon filters that I picked up from Marine Depot liquidation sale.... including 1 micron sediment and carbon filters, and an extra mixed DI cartridge. I just need help determining which setup is best for me.
What is the biggest contaminant in your water?
 
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LeftyReefer

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According to our latest (2020) water report, nothing tested above acceptable limits.

2020 water report

Saying that, I guess the water report does show chlorine at .95 PPM, with levels of .87 - 1.04 being acceptable.
So maybe a second carbon block would help?
other than that, nothing in the water report jumps out at me as concerning or that I need to add extra filters for anything in particular.
 

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According to our latest (2020) water report, nothing tested above acceptable limits.

2020 water report

Saying that, I guess the water report does show chlorine at .95 PPM, with levels of .87 - 1.04 being acceptable.
So maybe a second carbon block would help?
other than that, nothing in the water report jumps out at me as concerning or that I need to add extra filters for anything in particular.
For one, if the output water is 0ppm you are okay.

I didn’t mean acceptable levels, just if something is getting through your filter
 

Woodyman

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According to our latest (2020) water report, nothing tested above acceptable limits.

2020 water report

Saying that, I guess the water report does show chlorine at .95 PPM, with levels of .87 - 1.04 being acceptable.
So maybe a second carbon block would help?
other than that, nothing in the water report jumps out at me as concerning or that I need to add extra filters for anything in particular.
Do you monitor chlorine break through on your carbon block?

A second carbon block or additional DI would be my vote without knowing any of the finer details.
 

nereefpat

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For what it's worth, most of us have 2 carbon blocks. Chlorine is hard on RO membranes if it gets through the carbon stage.
 
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LeftyReefer

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Well in that case, sounds like a second carbon block is the way to go.

My first carbon block is a 5 micron, but I also have a new .5 micron carbon block ready to go.

So my new setup will be;
5 micron sediment filter
5 micron carbon block
.5 micron carbon block
RO
DI

thanks!
 
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LeftyReefer

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Do you monitor chlorine break through on your carbon block?

A second carbon block or additional DI would be my vote without knowing any of the finer details.

I have not tested/monitored for chlorine breakthrough. I guess I didn't realize that was a thing that needed to be checked.... i've only had a RO/DI for a few months. Can you recommend a chlorine test for this use?
 

Woodyman

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I have not tested/monitored for chlorine breakthrough. I guess I didn't realize that was a thing that needed to be checked.... i've only had a RO/DI for a few months. Can you recommend a chlorine test for this use?

Chlorine test strips do the job good enough. You can buy more precise test kits if you wish. But generally it's recommend to change your carbon block if you get 0.1 or above of chlorine after your carbon.

Spectrapure has an easy to use test kit or you could pickup some test strips from Amazon.

You want to monitor and change based off chlorine because chlorine will kill a RO membrane, leading you to replace your RO membrane prematurely, carbon blocks are cheaper, and will extend the usable life of your membrane!
 

Buckeye Hydro

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Well in that case, sounds like a second carbon block is the way to go.

My first carbon block is a 5 micron, but I also have a new .5 micron carbon block ready to go.

So my new setup will be;
5 micron sediment filter
5 micron carbon block
.5 micron carbon block
RO
DI

thanks!
Suggest you use a 1 micron or 0.5 micron sediment filter in your set up, As you listed it, the second carbon block is acting as a sediment filter for any sediment between 5 and 0.5 micron.
 
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LeftyReefer

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Suggest you use a 1 micron or 0.5 micron sediment filter in your set up, As you listed it, the second carbon block is acting as a sediment filter for any sediment between 5 and 0.5 micron.

OK, thanks. but now that has me thinking even more....

If I'm going to use a .5 micron sediment filter as my first stage... is there any reason a couple of 10 micron carbon blocks wouldn't be OK after it? If stage 1 is trapping anything over .5 micron, then why the need for anything better than that after it?

Wouldn't this setup be OK? (and cheaper than running more expensive .5/1 micron carbon blocks)
#1 .5 micron sediment filter
#2 10 micron carbon block
#3 10 micron carbon block
#4 RO
#5 DI

lf stage #1 is trapping any particle over .5 micron... why can't i just use (cheaper) 10 micron filters after it?
Or is there still some benefit to using the lower micron filtering carbon blocks?

thanks!
 

Buckeye Hydro

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A "micron" is a unit of measure - it is one millionth of a meter. The micron rating of sediment filters and carbon blocks is a measure of the diameter of the "holes" in the filter. Sediment smaller than the rating can pass through. About 85% of the sediment of the micron rating and larger will be captured by the filter.

The concept of successive filters having smaller and smaller pore sizes is a good one, but it applies only to sediment filters. You can find well-known vendors out there who do not understand this.

But there is more to carbon blocks than their pore size. You'll typically find that the larger the pore size, the less actual carbon there is in the block, and the lower its chlorine capacity will be.

So, to answer your question, yes - using two 10 micron carbon blocks would be ok - but just make sure you don't flow water through the block(s) faster than they can treat it, and make sure you keep up on changing them out more often. You may find using better (lower micron rating and higher chlorine capacity) may be a better value for you.

The discussion above assumes your tap water is treated with chlorine, rather than chloramine. If you have chloramine, then we need to have a different discussion (https://www.buckeyehydro.com/chloraguard-chloramine-carbon-block/).
 
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LeftyReefer

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My local water test only showed chlorine, no chloramine.
The last test (2020) showed chlorine at .95 PPM, with levels of .87 - 1.04 being acceptable.

Sounds like I'm better off sticking with better chlorine blocks too.

thanks!
 
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LeftyReefer

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I reconfigured my RO/DI setup a few weeks ago and have been running with 5 stages since.

I've noticed since winter has started, that the water coming into the house is a lot colder now...
I measured the incoming water and it was down to 52F. My RO/DI production has slowed a bit due to the colder incoming water, but I'm actually getting 0 TDS water out of my RO membrane now.... even before running through the DI stage. I'm guessing the colder water is helping the RO membrane reject more dissolved solids.

Question:
So now that I'm getting 0 TDS after my RO membrane... is there any reason to keep running the water through the final DI stage? Does running 0 TDS water through DI resin still deplete the resin? Or since it's not removing any dissolved solids, it's not being depleted at all?

During the summer, my incoming water was always over 70F and around 100 TDS.
now, during winter, my incoming water is low 50's F and around 80 TDS.
 

Woodyman

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I reconfigured my RO/DI setup a few weeks ago and have been running with 5 stages since.

I've noticed since winter has started, that the water coming into the house is a lot colder now...
I measured the incoming water and it was down to 52F. My RO/DI production has slowed a bit due to the colder incoming water, but I'm actually getting 0 TDS water out of my RO membrane now.... even before running through the DI stage. I'm guessing the colder water is helping the RO membrane reject more dissolved solids.

Question:
So now that I'm getting 0 TDS after my RO membrane... is there any reason to keep running the water through the final DI stage? Does running 0 TDS water through DI resin still deplete the resin? Or since it's not removing any dissolved solids, it's not being depleted at all?

During the summer, my incoming water was always over 70F and around 100 TDS.
now, during winter, my incoming water is low 50's F and around 80 TDS.

Keep the DI it will still remove traces that aren't picked up by your TDS meter. Our TDS meters measure whole numbers and depending on the unit have different levels of accuracy, just like other test kits. So it may say "0" TDS but it could be +/- 2ppm or higher/lower depending on the unit.

The DI will just help to further polish your water which isn't a bad thing, and feeding the DI with "0" TDS will cause the resin to exhaust much slower, so it will last longer between changes.
 
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KStatefan

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I reconfigured my RO/DI setup a few weeks ago and have been running with 5 stages since.

I've noticed since winter has started, that the water coming into the house is a lot colder now...
I measured the incoming water and it was down to 52F. My RO/DI production has slowed a bit due to the colder incoming water, but I'm actually getting 0 TDS water out of my RO membrane now.... even before running through the DI stage. I'm guessing the colder water is helping the RO membrane reject more dissolved solids.

Question:
So now that I'm getting 0 TDS after my RO membrane... is there any reason to keep running the water through the final DI stage? Does running 0 TDS water through DI resin still deplete the resin? Or since it's not removing any dissolved solids, it's not being depleted at all?

During the summer, my incoming water was always over 70F and around 100 TDS.
now, during winter, my incoming water is low 50's F and around 80 TDS.

I would continue to run the the DI stages. It will not do much but if something were to change it would do its job.

As your water temperature goes down your production will go down but your rejection rate will go up.
 

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