Where's my rain? in General Carnivorous Plant Discussion Posted June 20, 2018 · Report reply I have been trying to work out if boiling water to precipitate carbonate will reduce TDS sufficiently. Hs anyone with a TDS meter done the experiment? It appears that if there is enough calcium in solution (as should be the case in a limestone/chalk aquifer, as in most of SE England) it should be possible to get bicarbonate down to 80 TDS, at which point atmospheric CO2 levels prevent it going lower. So by this, boiling water and letting the carbonate precipitate out would work for water for the short term at least. Does anyone know if this is true or not?