Biocide Dosing Calculations

I am currently working on redesigning a biocide pretreatment system for reverse osmosis.

Apart from the ​usual ​parameters, ​should I take ​into consideration any ​other ​parameters such as ​Oxidation ​Reduction ​Potential (ORP) ​levels? Or temperature for calculations?
How much do they affect the system and how good is the calculation estimation without them?