Tds just went to 1

[doubleshot00]

Ive had my rodi system (Koolermax ar-122 6-stage) for a few months now installed the middle of April and the tds just went to 1. I ordered more filters and di resin but what do i change? All the filters or just some of them.

The manual says sediment needs to be changed every 6-12 months, carbon blocks 12 months and di filters are color change from green to brown (looks still green to me). I did not order the membrane as it says every 2-3 years.

 

[littlebeard]

Hard to say without more information.
How are you measuring tds?
What's your input tds? (house water)
What's the tds after the ro membrane?
whats the tds after di? (I assume this is 1?)


At the very minimum your DI resin is shot assuming your tds reading is correct.

Do you use color changing DI resin?

 

[dwest]

Ive had my rodi system (Koolermax ar-122 6-stage) for a few months now installed the middle of April and the tds just went to 1. I ordered more filters and di resin but what do i change? All the filters or just some of them.

The manual says sediment needs to be changed every 6-12 months, carbon blocks 12 months and di filters are color change from green to brown (looks still green to me). I did not order the membrane as it says every 2-3 years.

So what are the six stages?
1. sediment
2. carbon block
3. RO membrane
4. DI
5. ?
6. ?

Personally, I would wait and replace the sediment and carbon after 6 months. Since the unit is less than 6 months old, I would try to replace the first DI resin.

@littlebeard responded as I was typing. Very good advice there also.

 

[doubleshot00]

So what are the six stages?
1. sediment
2. carbon block
3. RO membrane
4. DI
5. ?
6. ?

Personally, I would wait and replace the sediment and carbon after 6 months. Since the unit is less than 6 months old, I would try to replace the first DI resin.

@littlebeard responded as I was typing. Very good advice there also.

Hard to say without more information.
How are you measuring tds?
What's your input tds? (house water)
What's the tds after the ro membrane?
whats the tds after di? (I assume this is 1?)


At the very minimum your DI resin is shot assuming your tds reading is correct.

Do you use color changing DI resin?

Its just the TDS meter that was sold with the unit. Its after everything. In is 74-76 tds.

Tds in is Before all of this.
1. sediment (this does look brown was white)
2. carbon block
3. RO membrane
4. DI
5. DI
6. Membrane.
Tds out is after all of this.

This is city water

 

[Eagle_Steve]

Its just the TDS meter that was sold with the unit. Its after everything. In is 74-76 tds.

Tds in is Before all of this.
1. sediment (this does look brown was white)
2. carbon block
3. RO membrane
4. DI
5. DI
6. Membrane.
Tds out is after all of this.

This is city water

OK, so TDS is 74-76 from the tap? and 1 After the DI Resin?

If so, I would temporarly put the TDS meter in the line right before the DI resin. Need to know what the TDS is right after the membrane. While we really do not need it, it will let us look at the whole picture.

I know you said it is 6 months old, but there are a few things to look at. Espcially if the carbon was not rinsed via removing the hose from it to the RO membrane when setting it. While the little bit of dust will not do much, if there was a lot of dust for some reason, it could have impacted your RO membrane. Again, may not even be an issue.

Would rather have as much info as possible before recommending an action like "just change the DI resin and you should be good", is all.

Also, we can use the input TDS and the TDS after the membrane to figure out you RO membrane efficiency. This quickly lets us know if it is good or is having issues.

In additon, what PSI is your RODI being run at? Sometimes lower pressures can cause the rejction rate to go way down. This means that while you have low incoming TDS, there is not enough pressure to allow the RO membrane to function as best as it can, so you may just burn through DI resin a little quicker than if the pressure was optimal.

 

[doubleshot00]

OK, so TDS is 74-76 from the tap? and 1 After the DI Resin?

If so, I would temporarly put the TDS meter in the line right before the DI resin. Need to know what the TDS is right after the membrane. While we really do not need it, it will let us look at the whole picture.

I know you said it is 6 months old, but there are a few things to look at. Espcially if the carbon was not rinsed via removing the hose from it to the RO membrane when setting it. While the little bit of dust will not do much, if there was a lot of dust for some reason, it could have impacted your RO membrane. Again, may not even be an issue.

Would rather have as much info as possible before recommending an action like "just change the DI resin and you should be good", is all.

Also, we can use the input TDS and the TDS after the membrane to figure out you RO membrane efficiency. This quickly lets us know if it is good or is having issues.

In additon, what PSI is your RODI being run at? Sometimes lower pressures can cause the rejction rate to go way down. This means that while you have low incoming TDS, there is not enough pressure to allow the RO membrane to function as best as it can, so you may just burn through DI resin a little quicker than if the pressure was optimal.

Psi is around 70. Ill have to figure out how to measure the tds before the membrane.

And I guess my second big question is would you use the water. Ive read conflicting things like some people don’t worry until it reads 3-5.

 

[Eagle_Steve]

Psi is around 70. Ill have to figure out how to measure the tds before the membrane.

70 is not that bad, so that should not be an issue.

Fro the TDS, you say the RODI came with it's own meter? If so, there should be a tds sensor set into a "tee" somewhere. You would just move that "Tee" to the output line (the line that goes from the membrane housing to the DI cartridge) and note the reading.

After you run it for a few minutes to let it get an accurate reading and to eliminate the bit of TDS creep that happens, you can move it back to be where it was.

 

[Reefer Matt]

Trying to figure out why there is another membrane after the resin. I would change the di resins and check again. Carbon blocks should be changed every 6 months. Sediment filters as indicated by pressure gauge., di resin as indicated by color or tds. Membrane every 2-3 years.

 

[littlebeard]

I'm assuming this is your system?


DI resin is always after the RO membrane.
If you didn't wire the system, it should be like that.
Verify it is, if they are not change it.

What color are the DI resin stages now? I suspect the DI is exhausted.

 

[Eagle_Steve]

Trying to figure out why there is another membrane after the resin. I would change the di resins and check again. Carbon blocks should be changed every 6 months. Sediment filters as indicated by pressure gauge., di resin as indicated by color or tds. Membrane every 2-3 years.

Good catch. I totally missed that lol.

I wonder if it is a "water saver system" and it just looks that way.

@doubleshot00 can you get us some pics of the unit? Like a few from different angles?

 

[doubleshot00]

I'm assuming this is your system?


DI resin is always after the RO membrane.
If you didn't wire the system, it should be like that.
Verify it is, if they are not change it.

What color are the DI resin stages now? I suspect the DI is exhausted.

Yes thats it. No I didn’t change anything; just took it out of the box maybe idk what im talking about. The DI resin does not look brown to me.

iv only filled up my 44 gal brute maybe 10x is this normal wear and tear?

 

[doubleshot00]

Good catch. I totally missed that lol.

I wonder if it is a "water saver system" and it just looks that way.

@doubleshot00 can you get us some pics of the unit? Like a few from different angles?

Give me a min and ill get them.

 

[Tathamet]

OK, so TDS is 74-76 from the tap? and 1 After the DI Resin?

If so, I would temporarly put the TDS meter in the line right before the DI resin. Need to know what the TDS is right after the membrane. While we really do not need it, it will let us look at the whole picture.

I know you said it is 6 months old, but there are a few things to look at. Espcially if the carbon was not rinsed via removing the hose from it to the RO membrane when setting it. While the little bit of dust will not do much, if there was a lot of dust for some reason, it could have impacted your RO membrane. Again, may not even be an issue.

Would rather have as much info as possible before recommending an action like "just change the DI resin and you should be good", is all.

Also, we can use the input TDS and the TDS after the membrane to figure out you RO membrane efficiency. This quickly lets us know if it is good or is having issues.

In additon, what PSI is your RODI being run at? Sometimes lower pressures can cause the rejction rate to go way down. This means that while you have low incoming TDS, there is not enough pressure to allow the RO membrane to function as best as it can, so you may just burn through DI resin a little quicker than if the pressure was optimal.

I was actually just wondering how to figure out if my membrane needs replacing. So say I had 416 tds going in and 23 coming out before di (made up numbers). 23/416*100 = 5.53% so 94.47% efficiency? Just curious at what point you would actually want to swap it out?

I’ll have to recheck what I’m at but I think I’m going on 4-5 years with my current membrane. So I’m assuming it’s about that time. Didn’t need to use it too much the first couple years I had it though.

 

[littlebeard]

iv only filled up my 44 gal brute maybe 10x is this normal wear and tear?

From the amazon site..
DI resin - Recommended refill every 400-500 gallons

 

[Eagle_Steve]

I was actually just wondering how to figure out if my membrane needs replacing. So say I had 416 tds going in and 23 coming out before di (made up numbers). 23/416*100 = 5.53% so 94.47% efficiency? Just curious at what point you would actually want to swap it out?

I’ll have to recheck what I’m at but I think I’m going on 4-5 years with my current membrane. So I’m assuming it’s about that time. Didn’t need to use it too much the first couple years I had it though.

I swap mine out at 97%, but I make a lot of water, have a lot of very special to me anemones, and Di resin gets expensive lol.

The average Dow Filmtec Membrane is about 98% rejection at 50psi. You can get to about 99% at 85 or so psi (at least I did). There are other membranes out there with higher rejection rates (98.5-99) and at quite a bit higher cost, but nothing is going to be 100% rejection for the systems we are using.

With that said, it all boils down o how much you want to spend on DI resin. The more TDS you have after the RO membrane, the more you will have to replace the DI resin to keep output at 0 TDS.

 

[Eagle_Steve]

From the amazon site..
DI resin - Recommended refill every 400-500 gallons

That is soo off base it is not even funny. I am not trying to be mean or funny here either. But no one should ever use anything like that to determine when to change DI resin.

There is no way anyone can tell you how much water will deplete your DI resin or how long. it will take for it to deplete. Especially mixed bed resin.

Mixed bed resin in Anion and Cation resin mixed to about 50/50. But there are tolerances in that as well, so you may have more of one than the other.

Then you have to account for the incoming TDS into the resin. While you can figure out what is in that TDS with some very extensive testing, that will only apply to your water in your house, at that exact tap where you are pulling the water from. You change taps in the house and the incoming TDS can change.

Now figure all of that and go to your neighbors house. They may have less or more TDS, even at the water main. More or less pipe from the water start point, etc. etc.

Then take that and expand that to all of the local water municipalities across the globe.

Now take into account that the TDS after the RO membrane may be more of a positive charge, so it is bound to the cation resin and that depletes first. Yet, the anion resin is still good but useless, as the TDS will not be "pulled to it, as they are both positively charged.

Way too many variables to say "change every 400-500" gallons


With all that said, a standard rule is to change the DI resin when you see 1 tds after it. And do not forget to flush the membrane for a few minutes before making water. The latter will help prolong the life of the membrane.

 

[doubleshot00]

Good catch. I totally missed that lol.

I wonder if it is a "water saver system" and it just looks that way.

@doubleshot00 can you get us some pics of the unit? Like a few from different angles?

 

[doubleshot00]

Good catch. I totally missed that lol.

I wonder if it is a "water saver system" and it just looks that way.

@doubleshot00 can you get us some pics of the unit? Like a few from different angles?

 

[doubleshot00]

Good catch. I totally missed that lol.

I wonder if it is a "water saver system" and it just looks that way.

@doubleshot00 can you get us some pics of the unit? Like a few from different angles?

 

[doubleshot00]

With all that said, a standard rule is to change the DI resin when you see 1 tds after it. And do not forget to flush the membrane for a few minutes before making water. The latter will help prolong the life of the membrane.

What do you mean by “flush the membrane “?

I see so many post where people change everything and they get like 1-5tds after the filters have been changed.

Imo this part of the hobby is really lacking.