This is why I switched from MC2 to MasterBlend. The MB mfgr says you can dissolve 2.5 lbs of it into 1 gallon of water to make a stock solution because the Ca and Mg are separate. I put 50g of MB into a 125ml bottle and top it off with RO water. Then it is 5ml/1tsp per gallon to get the recommended 2g/gal concentration. Same with a bottle of CaNO3 solution and another with half as much MgSO4. I find this easier than the MC2 which was too dusty, didn't dissolve quickly enough, and needed more Mg added anyway. It is cheaper, too.