the problem a lot of people have with dry
nutrients are self induced... If you mix your nutrients into cold water they will not always disolve properly. If you let your dry nutrients get moist in their container they will not disolve as easily since they will clump a little.
I would try getting some warm water to mix the nutrients in (like 1 gallon of water to warm and premix your nutrients) Then after you get that disolved well in there mix that slowly into the rest of your mix, and let settle to normal temp before adding to your main res.
That is my thoughts on relieving some of the complaints people have with dry nutrients. They are designed to disolve, but 60 F and 130F water disolve salts at MUCH different rates.