Listen, there is no ...

Listen, there is no established standard and if you see any then it is just a guide. However, your best bet under the circumstance is to carry out breakpoint chlorination experiments at different seasons depending on what seasons you have and establish the optimum dose per liter  you may need at a particular season. Remember, in the parlance of water treatment two things are most important quality and economy, with regards to quality we are specifically talking about disinfection every thing you do is all in an effort to attain 99% efficient disinfection. Chlorine cost money and a lot at that, therefore establish your chlorine demand per litre and all other things could be added onto that.