Ph control kit...

I just bought a "General Hydroponics PH control kit"

and it occurred to me to ask before I used it....(because of a bad CalMag experience)

this is ok for soil right? not just hydro?

yes its ok for soil and hydro.

ok, here's another logistical question....

when I test my feeding mixture Ph in the vile.... and it turns the correct color...
can I then use the liquid in the vile? or do you discard due to the testing solution?