ok .. so far it seems confirmed 500ppm is the common US scale..
by common i refer to the ppm scale you are gonna get if say, ordering a pen from the big river
700ppm is the common UK / european scale ... great. oh yeah, australia is a dog's breakfast...
since is north american based, i am leaning heavily to the 500 ppm scale as standard for the thread.
I would default to EC, honestly. Then you know what it is, and there is no confusion over conversions. If someone wanted TDS or PPM, they can then do the math.
The other option is all 3. 1EC/500TDS/700PPM, or 1.5EC/750TDS/1050PPM, etc.
Now this may not be "right", but when I read things it seems that the naming conventions are different.
- EC is just that, EC.
- TDS is the 500 scale from EC.
- PPM is the 700 scale from EC.
Greenleafs calculator supports measurement in all 3, plus others. Either way, for any of this EC/TDS/PPM is more an afterthought, unless there is a problem.