TDS meters

[johnydrink]

Hello,
in some forum threads some users write that TDS meters are 10-15$ from amazon and also on one article in Brunwater is written something similar(but there the recommended price is 20-30$ - https://www.brunwater.com/articles/tds-meter-do-you-need-one ). I checked some well-known brands like Apera and the cheapest Apera meter is 70$ - https://aperainst.com/tds20-value-pocket-tds-tester-meter and that's why I wonder if the 10-15$ TDS meters from Amazon will be accurate enough and do they need calibration similar to the calibration of PH meters( PH meters should be calibrated quite often). I have read some old threads where AJ Delange tells the 10$ PH meters are complete trash and I ask myself if the case with the 10$ TDS meters is the same. Can you recommend me some brand that from your personal experience is accurate enough for checking relatively reliably the tap water at home and RO water and that will last long enough? By the way, do you calibrate your TDS meter and if so, how often?
Thank you for your attention!

 

[IslandLizard]

From what I've read over the years, the cheap $10-15 TDS meter will suffice to check your (RO) water for ion content.

With pH meters it's an entirely different story. $10 pH meters are pretty much useless for (home)brewers. The main issue is they are difficult to calibrate because they tend to keep drifting. IOW, they are difficult or about impossible to stabilize enough to yield precise enough readings we're looking for.

 

[mac_1103]

I'm no expert, but several people who are experts have repeatedly posted that the inexpensive TDS meters are just fine. All due respect to Mr. DeLange, but he hasn't been seen around these parts for a while. Maybe a $10 meter in 2025 is better than a $10 meter was circa 2015?

 

[MaxStout]

TDS meters are a lot simpler than pH meters (the former simply measures electrical resistance of the water and calculates dissolved solids). A $10 TDS meter is a lot more reliable than a $10 pH meter. No comparison.

 

[johnydrink]

So, you all claim that for home use I do not have to buy some calibration solutions or something like that? Just to order the 10-15$ TDS item and what is inside the package is completely enough?

 

[cire]

So, you all claim that for home use I do not have to buy some calibration solutions or something like that? Just to order the 10-15$ TDS item and what is inside the package is completely enough?

No, not totally. Cheap TDS meters are fine, I've used both of mine for over 10 years and they do their job. The down side is that they are mostly calibrated for saline solutions, not for potable water. I calibrated one for my water after sending a sample for analysis and keeping some for calibration purposes. My water supply is from a borehole, but varies dependent upon rainfall, but in this way I can quite accurately determine the minerals levels in the supply.

If all you desire is to check the performance of an RO system or the like at low mineral levels, then there is no reason to recalibrate the instrument you receive, but it is possible to use them for more complex reasons, and cheap ones are perfectly accurate for homebrewers.

 

[InspectorJon]

@Buckeye_Hydro is a well respected HBT sponsor selling water treatment systems and the like. I have heard him recommend the cheap TDS meters for monitoring RO system performance.

 

[MaxStout]

You can always check your TDS meter in some distilled water--should read zero. But the meters are basically no-maintenance. Unlike pH meters which have sensitive probes that need to be kept in solutions and must be replaced from time to time, TDS meters just have a pair of metal electrodes that last a long time. After use, just rinse off with distilled or deionized water, let it drip dry, then put away.

 

[DuncB]

I've got a couple of these cheap TDS meters.
Never used them, partly because I'm not using RO and really not sure what I can use them for.
I was given them by a brewer closing down.
Any suggestions?

 

[InspectorJon]

The TDS meter reads Total Dissolved Solids in the water. The meter will tell you how much "stuff" is in your water but it will not tell you what that stuff is. It can give you an idea if you have hard or soft water. Filters and RO systems should remove most or all of these solids. One can use the meter to measure treated water to be sure the filter or other treatment system is functioning properly. We use a Zero brand water filter. Our tap water measures only around 70 on the meter, which is pretty low. It measures 0 when it comes out of the filter. We check the post filtered water periodically and when it gets to 6 or 7 we replace the filter.

 

[Buckeye_Hydro]

Yes - TDS meters are robust and not at all like the much more troublesome pH meters.

We stock both handheld and inline TDS meters and they all work well. We find that inline meters tend to be used more often, while handheld TDS meters tend to get tossed in a drawer and forgotten.

For small residential-scale RO systems a two-probe inline meter (the DM1, DM2, and DM3) where probes mount into quick-connect tee's is typically ideal. We can configure these three meters for use on 1/4", 3/8", and 1/2" outside diameter tubing. One probe reads the feedwater, and one probe reads the permeate (RO water). With these two numbers you can calculate the rejection rate and know when your RO membrane needs to be replaced.

Russ

 

[DuncB]

@InspectorJon

Great idea to use it to test the water filters, we have one in our fridge and the jug ones.
Thank you.

 

[mabrungard]

As mentioned above, a TDS meter is far less complex than a pH meter. A $10 TDS meter could be reliable, but I'd go with a little more reputable and reliable instrument. That's why I suggest a meter in the $20 to $30 range is probably the way to go.

Read more here: https://www.brunwater.com/articles/tds-meter-do-you-need-one