The parameters relevant to plants (EC, pH, chloride, etc.) are usually in the secondary standards, rather than the primary standards most important for human health.
San Jose groundwater is terrible, EC ~ 700 uS/cm out of the tap. I wrote
to model the custom fertilizer blend that I'm developing now, since the cal/mag in the water plus the phosphate from the acid I use to neutralize the carbonate significantly shift the nutrient profile. That's obviously beyond typical houseplant practice, but professionals growing in non-soil media (nurseries, vegetable growers, etc.) do roughly the same.
https://www.sjwater.com/sites/default/files/2021-06/ccr.pdf
The parameters relevant to plants (EC, pH, chloride, etc.) are usually in the secondary standards, rather than the primary standards most important for human health.
San Jose groundwater is terrible, EC ~ 700 uS/cm out of the tap. I wrote
https://hydromisc.github.io/hydromisc/doc/nutrient-calculato...
to model the custom fertilizer blend that I'm developing now, since the cal/mag in the water plus the phosphate from the acid I use to neutralize the carbonate significantly shift the nutrient profile. That's obviously beyond typical houseplant practice, but professionals growing in non-soil media (nurseries, vegetable growers, etc.) do roughly the same.