TDS Meter accuracy

[Waynerock]

My local water is supposed to be rated A (28732) and I got a new TDS meter and its reading 32 right out of the tap. I used it on a bottle of Smart Water and it came back as 22. Does that sound right? Is there any way to test the TDS meter? Got the kinda cheep one off Amazon. 14.00 but rated 4.8 with several hundred reviews

 

[Ding2daDong]

This is normal. I used to live in a city with high quality water but none of them completely remove all the TDS. Then you would have DI water, if I'm not mistaken.

 

[Gareth elliott]

Smart water is going to be a poor comparison for tds. They add a lot of salts back in after the ro process so it tastes like water. But my own tds except when chemicals are refreshed is quite similar out of the tap. Just ro membrane i get 1 tds.

 

[Waynerock]

Thanks guys I have had it with having to fight to get water and bought a 4 stage rodi and before I quality check the unit output I want to make sure this TDS meter is functioning correctly

 

[Gareth elliott]

Thanks guys I have had it with having to fight to get water and bought a 4 stage rodi and before I quality check the unit output I want to make sure this TDS meter is functioning correctly

If out and about can pick up a gallon of distilled water. Most i have used vary between 1-5 tds. There are some random ones around 10.

 

[JamieC]

I don't know what earns water a rating of "A", but mine out of the tap is around 30. I run 2 1 micron chloramine carbon blocks on my RODI system and my TDS is between 0 and 1 before entering the RO membrane. I still push it through DI resin, but I'm not sure it's doing much. I'm grateful because some folks deal with TDS in excess of 300 and burn through RO Membranes and DI resin.

I will add that I have 4 different TDS meters installed on my RODI unit and water mixing station. I've had mixed results using the TDS pen I purchased off Amazon.

 

[Waynerock]

If out and about can pick up a gallon of distilled water. Most i have used vary between 1-5 tds. There are some random ones around 10.

Yea I thought the smart water was straight vapor distilled I did not see the electrolytes added wording. And even though thats whats plants crave I dont think corals like them. I have been buying distilled for ato and buying sale water at LFS for a couple years and I can finally cut the umbilical and fend for myself.

 

[xxkenny90xx]

Sounds right to me. Try testing some arrowhead bottled water, thats a fun one...

 

[Gareth elliott]

I can finally cut the umbilical and fend for myself.

 

[rmurken]

I have grown skeptical of the need for absolute purity from an RODI unit or accuracy from a TDS tester. These tanks are complex biological systems. A few ppm TDS probably isn’t going to make a difference relative to the industrially-sourced components of salt mixes, and all the stuff, biotic and not, going on in the tank. Add on top of that feeding and sticking your hand in there (gloves or no) and you’ve eclipsed whatever survived your RODI rig.

 

[Randy Holmes-Farley]

I have grown skeptical of the need for absolute purity from an RODI unit or accuracy from a TDS tester. These tanks are complex biological systems. A few ppm TDS probably isn’t going to make a difference relative to the industrially-sourced components of salt mixes, and all the stuff, biotic and not, going on in the tank. Add on top of that feeding and sticking your hand in there (gloves or no) and you’ve eclipsed whatever survived your RODI rig.

Unless that 1 ppm TDS is copper. :(

 

[Randy Holmes-Farley]

Yea I thought the smart water was straight vapor distilled I did not see the electrolytes added wording. And even though thats whats plants crave I dont think corals like them.

Corals love most of them. Electrolytes is another word for salts, of which there are plenty in seawater. :)

 

[Waynerock]

Corals love most of them. Electrolytes is another word for salts, of which there are plenty in seawater. :)

The plants crave was from my favorite move which has also been pretty good at predicting the furure. Check out Idiocracy if you have not.

 

[rmurken]

Unless that 1 ppm TDS is copper. :(

How often does that happen?

 

[Randy Holmes-Farley]

How often does that happen?

It never happens that it is all copper. If even 1% of 1 ppm is copper (10 ppb copper), that may be too much.

My point is that 0 ppm TDS is important. The incoming water to the RO/DI can be above 1 ppm copper.

 

[Randy Holmes-Farley]

My local water is supposed to be rated A (28732) and I got a new TDS meter and its reading 32 right out of the tap. I used it on a bottle of Smart Water and it came back as 22. Does that sound right? Is there any way to test the TDS meter? Got the kinda cheep one off Amazon. 14.00 but rated 4.8 with several hundred reviews

On TDS meter accuracy, you can buy a calibration fluid to check it, but the zero point is never off. So I do not consider TDS meter ac curacy very important since by far the most important consideration is whether you are at 0 ppm TDS or not, not whether 10 ppm TDS is really 15 ppm TDS (which is a huge percentage error).

 

[rmurken]

It never happens that it is all copper. If even 1% of 1 ppm is copper (10 ppb copper), that may be too much.

My point is that 0 ppm TDS is important. The incoming water to the RO/DI can be above 1 ppm copper.

Ok, ok, fine. I concede you have a point. The EPA Lead and Copper Rule requires that at least 90% of outlets in a water system (or something like that) test below 1.3 mg/L copper, so I take your point.

 

[Plandauesq]

On TDS meter accuracy, you can buy a calibration fluid to check it, but the zero point is never off. So I do not consider TDS meter ac curacy very important since by far the most important consideration is whether you are at 0 ppm TDS or not, not whether 10 ppm TDS is really 15 ppm TDS (which is a huge percentage error).

Randy, can you please recommend a TDS meter to buy.

 

[Randy Holmes-Farley]

Randy, can you please recommend a TDS meter to buy.

I don't have a specific recommendation. Most are probably OK.

If you want it to do more (like tank salinity) it will have to be a more expensive type. Several old Orion conductivity meters (no longer made) often show up on Ebay. I used a model 128 for many years and liked it a lot.