Reverse osmosis water solves a lot of problems. Household RO systems are pretty wasteful, though; the pressure across the membrane is just the household water p

Reverse osmosis water solves a lot of problems. Household RO systems are pretty wasteful, though; the pressure across the membrane is just the household water pressure, so the ratio of waste:purified is around 3:1. Fancier RO systems with pumps achieve higher pressure, and thus more favorable waste ratio. Those professional systems are way too big for me, but perhaps I could build something. I believe that professionally, RO isn't used to solve excess calcium, carbonate, sulfate, etc., since it's cheaper just to neutralize the carbonate with acid and adjust the fertilizer salts appropriately. RO is used to solve excess sodium, chloride, etc., since the source water is already above the final desired concentrations. I'm running a single nutrient profile for all my plants, regardless of life stage--I can scale all the element concentrations together, but I can't adjust the ratios. My yields would be better if I adjusted as you say, though. At some point I should add a third fertilizer part and dosing pump.