Hans,
my own experience tells me that it's a good idea to make two stock solutions for your bleach - one with permanganate (dichromate in my case), one with acid. They keep well, and you can make them, for example, 10X concentrated. That means that to get 1 liter of working solution, you take 1 part (100 ml) of permanganate solution, add 1 part of acid stock, and 8 parts of water. After using it, you simply discard it, and make a fresh one from stock solutions each time. The relatively large amounts of chemistry to make stocks eliminate the need in weighing out the small quantities, and it's very convenient to measure out stocks.