A Fertilizer Discussion Reprise

[wisdomseeker]

Originally Posted by estación seca

There is no such thing as a PPM meter and there is no such thing as a TDS meter.

I'm confused about this, and don't fully understand.

There are several quality TDS bench meters (various brands) that are frequently used in the water/wastewater field that are fairly accurate with their test results.

Relationship Between TS, TSS and TDS

Solids, Total and Dissolved (TSS and TDS) - Water Quality Parameters | Hach

[estación seca]

Originally Posted by wisdomseeker

I'm confused about this, and don't fully understand.

There are several quality TDS bench meters (various brands) that are frequently used in the water/wastewater field that are fairly accurate with their test results.

Relationship Between TS, TSS and TDS

Solids, Total and Dissolved (TSS and TDS) - Water Quality Parameters | Hach

This is my point exactly. The only way to measure dissolved solids is to evaporate all the water, then weigh the residue. When people discuss a "TDS meter" they imagine a device similar to a pH meter that they stick in a glass of water, then read a number off a screen. There is no such TDS meter.

The "TDS meters" available on Amazon and shown above in other posts measure electrical conductivity, not dissolved solids. Electrical conductivity can't be converted to a TDS reading without knowing the exact composition of the minerals suspended in the water.