I ask because buying Maurten 320 and splitting them in half is more economical than buying Maurten 160. I’m assuming I can save half for use a day or two later.
Yes, so long as you maintain the ratio then it’s fine.
I reached out to them recently to ask about making a concentrate and then diluting on the go for Ironman distance events. They recommended mixing 3 sachets in 750ml of liquid (one at a time with 250ml of liquid to ensure that it all mixes and can be marked off in the bottle) and then mixing 250ml of this with an extra of 250ml at each aid station/when you get more water.