Dumb question but I need to ask

[Hilltopreef90]

I have a 6 stage RODI system, I change the filters and resin about every 6 months. I have a TDI meter and when switched to the out position it reads zero when switched to the in position it said 34 last night (I may have read it wrong it was hard to read but it definitely said 0 when set to out)
I’ve always assumed that out means the water going out that’s already run through all the filters.
Am I reading the meter correctly?

 

[Tamberav]

Depends where it is connected. Mine has 4.

Tap
After pre filters (before membrane)
After Membrane
After DI

Basically I can calculate how well the membrane is working since I have numbers before it and after it which tells me when to replace it. I can also verify my final TDS is zero.

I am not sure if yours is measuring before and after the membrane so you know when to replace it or if it’s just trying to give you a final read. May help to know the brand or there should be a manual you can check. You can also just trace where the lines are connecting among the filter.

 

[Hilltopreef90]

Depends where it is connected. Mine has 4.

Tap
After pre filters (before membrane)
After Membrane
After DI

Basically I can calculate how well the membrane is working since I have numbers before it and after it which tells me when to replace it. I can also verify my final TDS is zero.

I am not sure if yours is measuring before and after the membrane so you know when to replace it or if it’s just trying to give you a final read. May help to know the brand or there should be a manual you can check. You can also just trace where the lines are connecting among the filter.

My tds meter is on the last canister it’s a system from brs

 

[WVNed]

HM Digital Inline Dual TDS Meter - Instantly know the purity of your water, before and after the deionization stage.

 

[Ultra Aquatics]

My tds meter is on the last canister it’s a system from brs

Yes you are reading it correctly. TDS should be 0 after the last stage. It’s normal to have TDS before the DI.

 

[KStatefan]

Sounds like you are reading it correctly. Use that meter to determine when you need to change resin instead of just doing it every 6 months.

 

[Coxey81]

I have a 6 stage RODI system, I change the filters and resin about every 6 months. I have a TDI meter and when switched to the out position it reads zero when switched to the in position it said 34 last night (I may have read it wrong it was hard to read but it definitely said 0 when set to out)
I’ve always assumed that out means the water going out that’s already run through all the filters.
Am I reading the meter correctly?

I have a six stage as well. And if yours has the same stages as mine this is where you want your tds meters and what you should be looking for. I have two tds meters with a in and out, but one meter with three sensors would really make more sense.

1. Sediment Filter
2. Carbon Block
3. Carbon Block

*Pressure Gauge
*TDS meter 1 IN sensor (will measure incoming TDS since Sediment and Carbon blocks don't remove TDS

4. RO Membrane

*TDS meter 1 OUT sensor (will measure TDS removed by RO membrane. Should be about 98% less than in, change when drops to 95%)

*TDS meter 2 IN sensor (measures same as last meter and measures the TDS going into DI resin stages

5. DI resin (mixed bed, BRS standard di resin)

6. DI resin (mixed bed, BRS standard DI resin)

* TDS meter 2 OUT sensor (measures final TDS and let's you know that your DI resin is still working when comparing to IN. Should read zero.

For example, my First in sensor reads about 100, the out sensor after RO membrane reads around 2 (98% less than in)

Then my second IN sensor reads 2 cause it is placed in the same spot as the out of meter 1. (Between RO membrane and DI stage 1) And the out sensor on meter two after the 2 DI resin stages reads 0.

*Note, my DI resin stages are linked together with no way to put a sensor between them... but if you could, then you could see how well each stage was.doing at removing TDS.

 

[Cell]

BRS units typically have the sensor pre and post DI. So after RO, your TDS is 34 and the DI drops it to zero. 34 seems a bit high to me, I get about 5 TDS post RO, but everyone's water source is different.

 

[PanhandleReef]

*Note, my DI resin stages are linked together with no way to put a sensor between them... but if you could, then you could see how well each stage was.doing at removing TDS.

I separated my DI resin so I could put a meter in between them. Just take the screws out of the top, take off the link fitting and rotate the canister assembly 90 degrees. Order the elbow fittings that screw in and connect RO line. For me it was far more valuable to see when I need to replace DI of the first canister than having two meters read the same water.
Good explanation of your meter setup and what you read for the OP.

 

[Coxey81]

I separated my DI resin so I could put a meter in between them. Just take the screws out of the top, take off the link fitting and rotate the canister assembly 90 degrees. Order the elbow fittings that screw in and connect RO line. For me it was far more valuable to see when I need to replace DI of the first canister than having two meters read the same water.
Good explanation of your meter setup and what you read for the OP.

Ok cool, didn't know you could do that!

Thanks, I may do that later.

 

[Shirak]

I separated my DI resin so I could put a meter in between them. Just take the screws out of the top, take off the link fitting and rotate the canister assembly 90 degrees. Order the elbow fittings that screw in and connect RO line. For me it was far more valuable to see when I need to replace DI of the first canister than having two meters read the same water.
ood explanation of your meter setup and what you read for the OP.

Are you changing the first mixed bed before all of it has changed color?

The point of having two mixed bed is so you can use up the first one completely since it will often start showing a little tds before it's totally used up. When you have two, the second catches anything that the first one misses as it's nearing time for replacement. When you replace the completely used first canister the second one will be used up a little. It is then moved to the first canister spot and the new canister becomes the second.

 

[Coxey81]

Are you changing the first mixed bed before all of it has changed color?

The point of having two mixed bed is so you can use up the first one completely since it will often start showing a little tds before it's totally used up. When you have two, the second catches anything that the first one misses as it's nearing time for replacement. When you replace the completely used first canister the second one will be used up a little. It is then moved to the first canister spot and the new canister becomes the second.

Hard to tell what's going on for sure until the OP comes back. But if he is reading 34 coming out of his ro membrane and it is actually working correctly, then that would mean his incoming tds would be 34/.02 = 1700. That would be extremely bad water and not likely. More likely his RO membrane needs changing and that's why he is eating up his di resin.

Alternatively if he is reading 34 going into his RO membrane (which would be extremely good incoming water) he should be reading .02×34= 0.68 going into the di resin... which wouldn't be eating up his di resin at all.

So sounds like to me with the info we have his ro membrane needs changing.

ETA: well after reading again he just say he is changing every six months, not that it's color is changing or that he knows it needs changing for any reason... so he's not necessarily eating it up.

But if it's 34 coming out of the RO membrane that's no bueno.

 

[PanhandleReef]

Are you changing the first mixed bed before all of it has changed color?

The point of having two mixed bed is so you can use up the first one completely since it will often start showing a little tds before it's totally used up. When you have two, the second catches anything that the first one misses as it's nearing time for replacement. When you replace the completely used first canister the second one will be used up a little. It is then moved to the first canister spot and the new canister becomes the second.

I don't use color changing or mixed bed resin. I use Spetrapures MegaMaxCap, SilicaBuster, and Enduro DI

 

[Fredinva]

I don't use color changing or mixed bed resin. I use Spetrapures MegaMaxCap, SilicaBuster, and Enduro DI

I dont

I don't use color changing or mixed bed resin. I use Spetrapures MegaMaxCap, SilicaBuster, and Enduro DI

I don't know if one type di resin has an advantage over another, but the mixed/color changing resin certainly tells you when the resin needs to be replaced, along with the tds reading out of the resin.