Matt wrote:That sounds impressive, but I have no idea how 0.7 EC water translates to TDS. Do you know the conversion?
There are multiple conversion scales.
One scale states that EC 1.0 == 640 ppm TDS (most popular I have seen)
Another scale states that EC 1.0 == 500 ppm TDS (less common)
Yet another scale states that EC 1.0 == 700 ppm TDS (less common)
The highest conversion scale I have seen states that EC 1.0 == 750 ppm TDS (somewhat common in older equipment)
Depending on the conversion factor you use, 0.7 EC == 448ppm, 350ppm, 490ppm, or 525ppm
I apologize that I cannot give you a more exact number than that.
Matt wrote:
Isn't EC essentially the same as TDS except the numbers are different? I believe that one of the forum members here (95slvrZ28) wrote a formula for converting between EC and TDS of water...but my memory may be faulty.
EC = mS/cm = 1/(resistance across the resistor)
If you want to graph it, it is 1/x with a domain of 0<=x<infinity with 0 being a superconductive magic material with no resistance and infinity being a vacuum.
EC is the universal language. PPM meters read the EC and convert it into TDS. As you can see above, this conversion is rather inconsistent. I do not know why this is the case but a possible reason for this inconsistency could be differences in the electrical hardware. The equipment from each company could respond slightly differently at different ranges and the electrical engineers would have to alter their formula to make their results fall into the TDS standard.
This sort of craziness is why I prefer data in the most raw form that I can manage to understand in order to avoid as many academic "opinions" as possible.