I disagree with many things on the article and have support my contentions.
PO4 does not cause algae(someone is a decade behind the times on that one), plants grow very well at GH's of 24-25, I had tap like that for a few years, taste bad to drink, but plants grew very well.
Sort of funny about swords not liking hard waters......I collected and extended the known range of Echinordorus berteroi in the Santa Ynez River system by about 30 miles, previously it was only documented from Lake Chachuma in Santa Barbara County CA. The water there is beyond anything you will find in either Rift lake. Some soda lakes might compare.
GH's were well above 800ppm and pH's were over 9.
This is the only CA native sword plant. It also occurs in Mexico and elsewhere.
If it does not like those conditions, why does it grow there naturally?
Rift lake's salt content is much less NaCl.
People here salt, and they think NaCl.
Most of the ions in the lakes are actually plant nutrients:
CO3/HCO3(a form of inorganic carbon many plants can use)