Aero Nutes Question

hey i got a question/opinion i'd like to ask.... if you have a say 25gal res. made out of a rubbermaid roughneck (like from home depot) and it is relatively filled up how does one then add new nutes to the reservior to get to the desired ppm without shocking the plants during mixing....

in other words, i'd rather NOT have to lift up the lid and haul the heavy res filled with liquid, pump and all, to the bathroom to dump current solution down drain and mix new solution while plants roots are hanging out somewhere because the tub they were in is now being refilled.......

any ideas?

I got a homemade aero system, check my pics.
What i did is use two containers, one for the plants that drains into my res.
Now wen i need to do a res change i move the plant onatiner to the sid and change my nutes. But if your smart buy two of the samecontainers for your nutes, like i do now, so you can fill the res with water, ph it, put in your nutes, then just move the top container to the new res container along with your pumps, and you wont ever have to worry about seeing your roots again until you harvest. Any other questions fel free to PM me.

I have a pump. It connects to a hose. I pump out the old nutes. I also have a 50 gallon RubberMaid barrel. 25 gallons of fresh RO water goes into the barrel and the fresh nutes are put in there as well. After the rez is pumped out, I pump the fresh mix into the rez. It takes about 20 minutes to do the whole thing and the only thing I carry is a four-gallon pail to fill up the barrel with the RO water.

Vi