As it has been said above, It's a common practice to mt your
tank back to your fuel container when your done flying for the
day. I really never saw if my fuel is dis-colored?? I use power
Master fuel in a metal can.. But I never noticed any major
dis-color when mting one container to the full one. Some
members that fly alot do leave their tank as is, but they
connect the pressure and fill lines together to keep it a close
system.. Guess you could do that, if it concerns you and if
you fly often..