QT water, should I use fresh slat water or old tank water?

[MadManMac]

I am setting up a QT tank for some new fish, and want to know if I should use the 10 gallons of fresh salt water, or use 10 gallons from my main tank and use the fresh salt water for a change? Any ideas are very much appreciated.

 

[quarryshark]

Start it from the main tank, you can use change water from the main or fresh mix.