I'm sure what the person meant was he/she mixes them into a jug that already has mostly water in it, because you should NEVER mix nutes raw!

I also have a 10 gallon system, and what I do is measure the Micro, dump it in while stirring. Then I measure up the Bloom and dump it in while stirring. And if I'm also adding Grow I measure it up then dump it in then stir. I use a long rigid plastic tube for the stirring.

I have a water pump in the res that constantly "stirs" as well as drips/streams to my growing tub. Thats how I do it anyway and it seems to work out just fine.