I do a lot of small runs with discharge where I use less than the minimum amount of ink required simply to cover the design on the screen. I find that I can't really reliably mix less than 200 grams, and some jobs only use 50 or so of certain colors. This basically means I had to find a way to save activated ink. I found that keeping activated ink in a fridge, sealed, and with a tiny amount of added water will last multiple months without issue. I have run tests with every color imaginable after long periods of time without any color issues. I usually add 1% activator and a spray or two of water from a squirt bottle, mix, and print. This is with Matsui, white and colors.