Provided is a fluid processing apparatus using a crystallization promoting medium (CPM) as a fluid processing medium. The apparatus comprises one or more column bed units in parallel connection, wherein the column bed units may be connected in parallel with a bypass flow path having a check valve, and except the first column bed unit, each of the column bed units is provided with a check valve upstream thereof. Also provided is a method for improving the efficiency of a CPM-based fluid processing apparatus having only one column bed unit. The method comprises: replacing the column bed unit of the CPM-based fluid processing apparatus having only one fluid processing column bed unit with: (i) a plurality of secondary column bed units in parallel connection, wherein the secondary column bed units may be connected in parallel with a bypass flow path having a check valve; and except the first secondary column bed unit, each of the secondary column bed units is provided with a check valve upstream thereof; or (ii) one column bed unit and a bypass flow path that is connected in parallel with the column bed unit and has a check valve. Also provided is a proportional check valve that opens proportionally as the pressure increases.