Why Is Desalination So Difficult? (Practical Engineering on YouTube)

Brady does a good job breaking down why RO desalination is energetically and operationally much better than traditional distillation. Only thing I didn't like that much was his discussion of salinity concentrations, as I feel like he built it down by defining what ppt meant relative to percentages, while I think that it being shown to the relative amounts of other dissolved solids like iron and hardness would show that sea water is an order of magnitude more laden with the dissolved solids. To me that is why RO membranes are absolutely miraculous despite the high energy requirements, because they can produce high quality fresh water from differing source water without there being much difference in each treatment process in the end. Running seawater through RO for desalination, versus well water removing hardness and nitrates would mainly differ on the pretreatment to remove suspended solids and then the proportion of reject water to permeate.