Hi, I'm just wondering can I substitute Na2SiO3.9H2O with Na2SiO3.5H2O.. I Have to make this solution for F/2 , Guliard&Ryther Medium.. which indicate to dissolve Na2SiO3.9H2O 30g/L.dH2O.. I can't get the Na2SiO3.9H2O reagent in my country.. but I can only find NaSiO3.5H2O.. Are they the same??