Spotlight on TDS Meters | BRStv

[randyBRS]

Hey everyone!

Today we're revisiting the TDS meters for your RODI unit, but with a bit more detail under the BRStv Spotlight series.

 

[mch1984]

My RO system is being installed Friday morning, I decided to go the more expensive route and am renting it. They are going to start with changing the filters and DI every 3 months. Well see if it can go any longer than that. It's a 7 stage 100gpd system. I ordered one of these and they said they would plumb it in for me.

 

[Mark Waltermire]

My RO system is being installed Friday morning, I decided to go the more expensive route and am renting it. They are going to start with changing the filters and DI every 3 months. Well see if it can go any longer than that. It's a 7 stage 100gpd system. I ordered one of these and they said they would plumb it in for me.

I have never heard of renting an RODI system. I’m just curious, but was it cheaper to go that route vs buying it outright?

 

[mch1984]

I have never heard of renting an RODI system. I’m just curious, but was it cheaper to go that route vs buying it outright?

In the long run, buying is cheaper by a long shot, renting is kind of convenience thing. They change the filters on a set schedule, if something breaks they fix it. They will change all the filter and DI on a set schedule, which for now is every 3 months. The typical is 6 months but us reefers are a little pickier lol. Up front is cheaper but in the span of 6 month you could have paid for one out right. I'm not a lazy person by any stretch but for whatever reason I get lazy changing the filters on the RO. Now I don't have to worry about me being lazy on it.

 

[Crabs McJones]

So on the back of the unit that you opened up to show the batteries, it said calibrate with NaCl. I know BRS sells calibration fluid, but how do you actually calibrate this unit? I have the single probe tds meter from BRS. Thanks @randyBRS

 

[WWIII]

I also have a couple questions about the inline tds meters. Is their accuracy affected by changes in temperature? Also, is there an average life expectancy for these inline tds meters, not just that they turn on and give a reading, but for accuracy as well? Another great video! Thanks

 

[Ridgeway]

Here I run a 4 stage TDS meter (2 units) the 3 as described above and then one more in the ATU reservoir, not paranoid at all

 

[Randy Holmes-Farley Verified Community Expert]

I also have a couple questions about the inline tds meters. Is their accuracy affected by changes in temperature? Also, is there an average life expectancy for these inline tds meters, not just that they turn on and give a reading, but for accuracy as well? Another great video! Thanks

Temperature impacts conductivity measurement, and stand alone units usually measure it and compensate for it. These inexpensive inline meters do not, so there is some error associated with that (that doesn't concern me, but it might concern some people).

IMO, high accuracy is not important in an inline meter to monitor an RO/DI.

0 ppm is always 0. Such as zero ppm TDS in air. If it ever reads anything else in air, the meter is broken, not just miscalibrated.

The 0 ppm TDS point is a fixed point in the method, so only the slope changes. Even if it is off by 50%, so that 2 ppm TDS reads as 3 ppm TDS or 1 ppm TDS, I don't think that will impact what one should do as a consequence of readings, which is primarily to change the DI when the TDS rises above 0 ppm.

 

[randyBRS]

So on the back of the unit that you opened up to show the batteries, it said calibrate with NaCl. I know BRS sells calibration fluid, but how do you actually calibrate this unit? I have the single probe tds meter from BRS. Thanks @randyBRS

I can't say that we've calibrated our in-line TDS meters here in the office and we haven't seen changes from their normal operating readings. However, if you'd like to calibrate them there are calibration instructions in the included manual. Here's a link to one from HM directly. http://hmdigital.com/wp-content/uploads/2016/11/sm1.pdf

-Randy

 

[Crabs McJones]

I can't say that we've calibrated our in-line TDS meters here in the office and we haven't seen changes from their normal operating readings. However, if you'd like to calibrate them there are calibration instructions in the included manual. Here's a link to one from HM directly. http://hmdigital.com/wp-content/uploads/2016/11/sm1.pdf

-Randy

Thanks Randy

Here are the instructions for anyone else curious
Calibration Your monitor was factory calibrated to 342 ppm (NaCl). This level is suitable for most tap water/filtered water applications. However, you may need to re-calibrate based on your needs, as well as from time-to-time to ensure best results.
1. Purchase a calibration solution from your dealer that is correct for your needs.
2. Disconnect the T-Fitting from its hose. Do not remove the sensor from the T! Ensure the orientation of the sensor to the fitting is correct, as in the illustration.
3.Turn on the monitor and place the T-Fittings (with the sensor in it) into the calibration solution. You will get a reading.
4. If the reading on the monitor does not match the solution, adjust the reading up or down by gently turning the orange screw on the rear of the monitor clockwise or counter-clockwise.
5. The monitor should read approximately 10% below the calibration solution. The monitor is designed for flowing water and this discrepancy will compensate for that. (NOTE – if you are calibrating with a flowing solution, ignore this).
6. Once the reading is correct, turn the monitor off and remove from the solution.

Your monitor is now calibrated

 

[Ryanbrs Verified Sponsor]

Thanks Randy

Here are the instructions for anyone else curious
Calibration Your monitor was factory calibrated to 342 ppm (NaCl). This level is suitable for most tap water/filtered water applications. However, you may need to re-calibrate based on your needs, as well as from time-to-time to ensure best results.
1. Purchase a calibration solution from your dealer that is correct for your needs.
2. Disconnect the T-Fitting from its hose. Do not remove the sensor from the T! Ensure the orientation of the sensor to the fitting is correct, as in the illustration.
3.Turn on the monitor and place the T-Fittings (with the sensor in it) into the calibration solution. You will get a reading.
4. If the reading on the monitor does not match the solution, adjust the reading up or down by gently turning the orange screw on the rear of the monitor clockwise or counter-clockwise.
5. The monitor should read approximately 10% below the calibration solution. The monitor is designed for flowing water and this discrepancy will compensate for that. (NOTE – if you are calibrating with a flowing solution, ignore this).
6. Once the reading is correct, turn the monitor off and remove from the solution.

Your monitor is now calibrated

Looks like they changed this a bit since last time I saw it.

At the factory, they calibrate with a flowing standard. The old instructions required you to do the same which just isn't feasible. Looks like they now say just calibrate to 10% lower to compensate. I'd also note the probes do read dramatically different inside the tee than outside the tee. It was almost 30% different last time I looked at it.

All in all, I would not attempt to calibrate these unless something is seriously wrong. I think most people are ten times as likely to decrease accuracy than increase it.

 

[Crabs McJones]

Looks like they changed this a bit since last time I saw it.

At the factory, they calibrate with a flowing standard. The old instructions required you to do the same which just isn't feasible. Looks like they now say just calibrate to 10% lower to compensate. I'd also note the probes do read dramatically different inside the tee than outside the tee. It was almost 30% different last time I looked at it.

All in all, I would not attempt to calibrate these unless something is seriously wrong. I think most people are ten times as likely to decrease accuracy than increase it.

Sounds good Ryan, thank you very much

 

[Jgarcia]

Will the tds ever change before it gets to the di resin? I have a 4 stage 150 gallon per day pre filterarion before the resin.
I’m wondering if there is a tell tail sign to tell me when the carbon filters or membrane is going bad

 

[randyBRS]

Will the tds ever change before it gets to the di resin? I have a 4 stage 150 gallon per day pre filterarion before the resin.
I’m wondering if there is a tell tail sign to tell me when the carbon filters or membrane is going bad

In most cases the best way to tell if a carbon block is exhausted is to test for chlorine or chloromine (using test strips) before the RO membrane. However, most reefers opt to change these out on a rotational schedule because it's much easier then periodically testing and filters are pretty low cost if changed 1-4 times per year. To know if your RO membrane is becoming exhausted, you would want to take note of the TDS reading when the filter is somewhat new, then over time and use you would see that reading rise. When it does rise, it is an indication that it's time to change the membrane.

-Randy

 

[AquaFX-PB]

Will the tds ever change before it gets to the di resin? I have a 4 stage 150 gallon per day pre filterarion before the resin.
I’m wondering if there is a tell tail sign to tell me when the carbon filters or membrane is going bad

Well testing for Chlorine before your RO membrane is kind of not helpful - if you test and and its present, its more than likely too late for the membrane - RO membranes chlorine tolerances are usually <.1 ppm

So figure out an approximate gallon usage for yourself, and put yourself on a scheduled filter change for the sediments and carbons - you can change your prefilters more often if you see a pressure drop on your pressure gauge happen before your scheduled filter change.

Any well working RO membrane should reject 'at least' 90% TDS (or 98.6% in ideal applications) if your membrane isn't removing at least 90% then I would replace (costing too much in DI resin), assuming it was working properly in the first place of course. ;Mask