Perhaps the most widely published and easy to use hard copy capacity curves for rating co-flow exchangers are the engineering notes developed by the Rohm & Haas Company. These notes depict the capacity of Type 1 porous anion resin as a function of caustic dose related to FMA, CO2 and SiO2. The triangle curves for IRA-402 show extraordinary capacity for silica, in some cases approaching the total capacity of the resin. Modern curves (by ResinTech and others), are in various software formats.