TDS Meter Accuracy

[jaw1990]

I bought a brs 5 stage ro/di unit. It has the built in TDS meter. It says my water coming in is about 8 TDS and going out is 0. I bought a handheld tds unit from brs as well. (Link below) the handheld unit seemed pretty accurate but now it seems to be all over the place. I checked tds at my mixing station and it said it was 0. I moved the bucket into my laundry room and it said it was 20 tds. Which tds meter should I believe. Thank you.

TDS-3 Handheld TDS Meter & Thermometer

The TDS-3 Handheld TDS Meter from HM Digital is a useful tool to spot check the TDS of your home water supply or RO/DI unit output. This unit features a digital display, built in thermometer, and comes with a carrying case. As with all HM-Digital products, the TDS-3 comes factory calibrated.

www.bulkreefsupply.com

 

[LeftyReefer]

Was anything in the bucket? a few drops of saltwater perhaps?

Have you checked the output of the RO/DI with your handheld? Did it read 0 coming out?

If nothing was in the bucket that added TDS, what is the bucket made from?

Are the in-line meters installed correctly? (not turned 90 degrees)

 

[mfinn]

I found ( at least a couple times ) that if I use a bucket or barrel to mix saltwater it seems to always show tds when adding 0 tds ro/di water.
It's like it's forever destined to be used for saltwater.

 

[Reeferbadness]

TDS meter is super sensitive. I usually test my RO/DI water (i have an inline tds meter but also double check that with hand held) using a new small plastic cup and test as it comes out of the RO/DI unit. My 55 G storage tank for the water always shows some small amoutn of tds due to it being located outdoors and not fully sealed.

 

[jda]

It does not really matter. Most will do a good job of letting you know that TDS is low at 0-1 and also that you need to change filters when they start to rise.

I change my filters when my water gets over 5, which could be 10 or 15 for all that I know. Once I do change the filters, the meter is at zero again.