How long do mixed nutes stay fresh?

For soil grow...I currently mix my nutes (Technaflora) in 1 gallon of distilled water. Thing is, I only feed once a week and then, only 1/2 gallon at a time. Will the other unused 1/2 gallon still be fresh when the next feeding comes around?

yup.......................

erm well, i did the same thing as u. i mixed canna bloom nutes with molasses. it didnt look pretty when i come back to water. it looked like shit. so i chucked that stuff on my flowers in my garden and made some fresh.

once i made fresh i only filled up half a gallon and just cut the nutes in half to suit the ratio of water to nutes.

Thanks for replying. Anybody else want to chime in?