actually i use TEA and it is good for litel quantity must be lower then 5% so if we take it as neutralizer %TEA = %Carbomer* 1,5 i did try Naoh and it make residu so i eliminate it from my choice about AMP may it can be in residu better then TEA according to some reaserch i did but still searching for AMP to be sure from that reasearch by doing experience so for AMP i had not experiences .
Actually for viscosty it depend on neutralizer , ph , % Carbomer , and type of carbomer i have idea about carbomer 996 but not for edt 2020 .
just make correct neutralisation then try to reach your optimal viscosity by starting from high viscosity product and decreasing the viscosity by diluating your product until you reach wanted viscosity then calculate the adequat % of carbomer of wanted viscosity i use this method it is too easy and fast .
Good futre product friend.
for your question you must reduce % of carbomer not reducing quantity of neutralizer , actually both will decrease the viscosity but if you just make bad neutralization with less needed neutralizer you will have high acid product wich can be harmfull.