Does this DI Resin look ready to replace?

Kayanarka

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Hi Folks. I am starting to see color change on my DI resin. I am not sure if it is time to replace now or if I can wait some. I bought 3 filters last night, everything except the membrane. I do not want to replace them if they still have life left. I assume carbon, sediment, and resin should be replaced together? The first two say replace about every 6 months, but I did fill my 250 on this filter set, so I imagine I should be sooner then 6 months.

Here is a photo of the resin right now.

Can you test your RO/DI water? If so how?

Can I manually back flush the membrane filter, or is that automatically done as it makes water?

As always, thanks in advance for the help.

20220108_115312.jpg
 

Woodyman

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Hi Folks. I am starting to see color change on my DI resin. I am not sure if it is time to replace now or if I can wait some. I bought 3 filters last night, everything except the membrane. I do not want to replace them if they still have life left. I assume carbon, sediment, and resin should be replaced together? The first two say replace about every 6 months, but I did fill my 250 on this filter set, so I imagine I should be sooner then 6 months.

Here is a photo of the resin right now.

Can you test your RO/DI water? If so how?

Can I manually back flush the membrane filter, or is that automatically done as it makes water?

As always, thanks in advance for the help.

20220108_115312.jpg

Before I answer all your questions let me start by saying that resin doesn't appear depleted. The color your seeing is just water in the housing. Resin should change to an orange/yellow color as deleted and will usually change from bottom up. Now I'm not sure on the specifics for that housing since it looks proprietary, but I imagine it works the same.

Now, what RO unit do you have, and does it have any pressure gauges or TDS meters?
 

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Hi Folks. I am starting to see color change on my DI resin. I am not sure if it is time to replace now or if I can wait some. I bought 3 filters last night, everything except the membrane. I do not want to replace them if they still have life left. I assume carbon, sediment, and resin should be replaced together? The first two say replace about every 6 months, but I did fill my 250 on this filter set, so I imagine I should be sooner then 6 months.

Here is a photo of the resin right now.

Can you test your RO/DI water? If so how?

Can I manually back flush the membrane filter, or is that automatically done as it makes water?

As always, thanks in advance for the help.

20220108_115312.jpg

Now to answer the rest of your questions.

1. Yes you can test your RO water. Each stage of filtration can be tested for efficiency and for knowing when to replace the individual filters.

For sediment you should be replacing when the outgoing vs incoming pressure has dropped ~10% or more.

For carbon you should be replacing when you have chlorine breakthrough above 0.1 ppm.

For RO membranes you should be replacing when the rejection % drops below 96, but can also be done below 98, or 97, some of that is up to personal preference and your water parameters. For example if you produce low TDS water from RO you may be able to wait until you get to 95 or even 90% rejection before replacing, the higher rejection the less work your DI resin will have to do, which again depending on your source water will lead you to make the best decision for your individual situation.

DI needs to be replaced whenever you read >0 TDS or if color indicating when you have ~1-0.5" left of unchanged resin in the cartridge.

2. Membranes can be automatically flushed or manually depending on how you build (or purchased) your system. They can also be modified after initial setup/purchase to add features down the line.
 

Woodyman

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Do you know any of your source water parameters?

Chlorine content, chloramine present, TDS, pressure?

Also are you using well or municipal?
 

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You need a TDS meter... ideally a triple inline TDS meter for ease of use. Measure your source water, post RO and post DI TDS. I don’t use color changing DI resin, I rely on my TDS meter to tell me when it’s time to change resin. Once it’s no longer producing 0 TDS water, the DI resin gets changed out.
 
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Kayanarka

Kayanarka

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This looks like what I need. Is it pretty acurate? Hold up overtime? What kind of numbers would I be looking for on the middle sensor? I assume the first one will just give me an idea of how awful my water is and the last one will tell me if I am at 0 or not?

Before I answer all your questions let me start by saying that resin doesn't appear depleted. The color your seeing is just water in the housing. Resin should change to an orange/yellow color as deleted and will usually change from bottom up. Now I'm not sure on the specifics for that housing since it looks proprietary, but I imagine it works the same.

Now, what RO unit do you have, and does it have any pressure gauges or TDS meters?
I have seen the units with guages but no mine is very basic, was in stock at the LFS, bought it the day I bought my 450xl and got into this hobby on a complete impulse.
20220108_151713.jpg

Do you know any of your source water parameters?

Chlorine content, chloramine present, TDS, pressure?

Also are you using well or municipal?
I think my town is using chloramine now, water is pretty nasty even for our consumption if not filtered at all. I have not tested it nor taken time to do any serious research on it. I do know with new filters and no pressure boost I make 5 gallons in 1 hour 20 minutes.
 

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This looks like what I need. Is it pretty acurate? Hold up overtime? What kind of numbers would I be looking for on the middle sensor? I assume the first one will just give me an idea of how awful my water is and the last one will tell me if I am at 0 or not?


I have seen the units with guages but no mine is very basic, was in stock at the LFS, bought it the day I bought my 450xl and got into this hobby on a complete impulse.
20220108_151713.jpg


I think my town is using chloramine now, water is pretty nasty even for our consumption if not filtered at all. I have not tested it nor taken time to do any serious research on it. I do know with new filters and no pressure boost I make 5 gallons in 1 hour 20 minutes.

With the 3 you would set 1 for feed water, 1 for water coming out of the RO, and one for water coming out of the DI.

The middle sensor you would be comparing to the first sensor and it would provide you with your membrane rejection %.

I like and find the HM meters accurate.

If your source water contains chloramines it would be best to add an additional carbon block to your system, but being that you have a proprietary setup that doesn't take standard filter cartridges it's not quite as simple to add/remove components.
 
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Kayanarka

Kayanarka

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Thanks for the advice. My LFS had a dual sensor in stock.

20220108_194931.jpg


I was wondering why I would need the triple sensor and I get home to read :
With the 3 you would set 1 for feed water, 1 for water coming out of the RO, and one for water coming out of the DI.

The middle sensor you would be comparing to the first sensor and it would provide you with your membrane rejection %.

I like and find the HM meters accurate.

If your source water contains chloramines it would be best to add an additional carbon block to your system, but being that you have a proprietary setup that doesn't take standard filter cartridges it's not quite as simple to add/remove components.
I could probably add an extra carbon only filter just before my current ro/di filter block with out too much effort, so I will see what I can find to do that. I can also put this sensor on the input and rejection water, and just use a hand held meter to see what the final product looks like. My wife has this that came with a zero water pitcher, think it would be accurate enough?

20220108_195956.jpg


Thank you all for the help, just another step closer to perfecting my reef keeping skill and tool sets.
 
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Kayanarka

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With the 3 you would set 1 for feed water, 1 for water coming out of the RO, and one for water coming out of the DI.

The middle sensor you would be comparing to the first sensor and it would provide you with your membrane rejection %.

I like and find the HM meters accurate.

If your source water contains chloramines it would be best to add an additional carbon block to your system, but being that you have a proprietary setup that doesn't take standard filter cartridges it's not quite as simple to add/remove components.
I have the sensor installed, and I am maybe a little confused? My input, water from the faucet, is reading 24ppm. My output, water rejected from the membrane, is reading 28ppm. Should it not be atleast a little better then the input? Or is that because the output of the membrane is concentrated "bad stuff"?
 

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I have the sensor installed, and I am maybe a little confused? My input, water from the faucet, is reading 24ppm. My output, water rejected from the membrane, is reading 28ppm. Should it not be atleast a little better then the input? Or is that because the output of the membrane is concentrated "bad stuff"?

Did you install it on the waste line by mistake?

There are 3 lines typically on RO housings. 1 is incoming feed water, 1 is rejected waste water that goes down the drain, and 1 is your product water which is normally 96%+ lower than the feed water.

So for example I'd your feed water is reading 100 TDS your product water should be reading in the range of 0-4 TDS
 

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If it is installed in the correct spot my next place to check would be that the RO membrane is properly seated in the housing.
 
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Kayanarka

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Did you install it on the waste line by mistake?

There are 3 lines typically on RO housings. 1 is incoming feed water, 1 is rejected waste water that goes down the drain, and 1 is your product water which is normally 96%+ lower than the feed water.

So for example I'd your feed water is reading 100 TDS your product water should be reading in the range of 0-4 TDS
Hi, yes, I thought we wanted to see what the membrane was getting rid of. So I want it between the carbon/sediment and the membrane, or between the membrane and the resin?
 

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Hi, yes, I thought we wanted to see what the membrane was getting rid of. So I want it between the carbon/sediment and the membrane, or between the membrane and the resin?

If you’re working with a 2 sensor inline TDS meter, place one sensor between the RO membrane product line (not the waste line) and the DI stage (this will give you your post RO membrane TDS reading) and one sensor after the DI stage (this will give you your post DI stage TDS reading). Use your handheld to measure TDS from your tap, this will give you your source water TDS.

With these 3 measurements, you will have all the data you need to determine efficiency of your RODI unit.

1 minus (the post RO TDS divided by the source water TDS) will give your your RO membrane’s rejection rate. This will let you know when It may be time for a new membrane. Knowing your post RO membrane TDS will also let you know how hard your DI stage needs to work and if you may benefit by adding additional DI stages to make your system more efficient. Your post DI stage TDS reading will let you know if you need to change your DI resin. As I mentioned in my earlier post in this thread, anything above 0 and I will swap out my DI resin.

If you want to make your setup even more efficient and prolong your DI resin life, you can add a DI bypass valve (not to be confused with a membrane flush valve). See my post here…

 
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