Does it matter where in the tank where I pour in the nutrients? I noticed that when I pour them in, I can see a little 'cloud' fall down to the bottom of the tank... So would pouring directly over the root system be of any benefit?
You shouldnt see that anyway, it is showing that you dont have a good circulation. which is needed in a planted tank to do the exact reasons - push the nutrients around effetcively.
as Gareth says above. Once the solution is in you may see a "heathaze" type effect but no clouds. Also the heathaze effect should last for a millisecond and then be shot all over and gone.
I just fill my syringe and squirt it in anywhere. No probs. let the filter/circulation do the work.