Your KH level is inconsequential when adding CO2. I run all my tanks on pure RO water and simply add some remineralising salts to up the GH to 3-4dGH. KH is 0.jh81271 said:hi ceg
the tank is 180ltr which as you say might be a little expensive long term !
i'l switch that gas back on.I had no kh for a while which was why i was only using easy carb .but everything slightly bettr as i now have a kh of 2.I presume tank is more settled now .4 would be better but hey!