No. That was my concern at first too. There was a thread somewhere on this, maybe LFPF, but IIRC the gist was that the parts weren't separated for longevity but for ease of replenishment. I don't recall the details, but I've kept a bottle combined for more than a year and it still worked fine (squeeze the air out before capping.)
Originally Posted by GarageBoy
I like to dilute more than 1+4 but that's a matter of taste. Some people use 1+6 or even 1+9. I don't like the midtones with 1+9. I like 1+6 fine but have tweaked mine to 1+5. YMMV of course.