Some nutes/additives will change the pH on their own as they are added in, VV.
If you adj the pH first and then add the nutes, you'll be chasing it around and possibly use more chems to get to the target point.
Losta Cal-Mag and Silica products will raise the pH. Some brands of Humics and fulvics will lower the Ph. You just gotta check each one out to see what effect, if any, it has on the base water.