I too mixed up the entire 10 liters and stored them in brown glass bottles of various sizes for more than a few years. When I noticed that they could go bad before I got them used up I started mixing them in small quantities straight from the concentrates. That solved the problem as long as I use the bottle of concentrate up within 2 years or so. It also reduces the amount of space under the sink that I used to store the chemistry. Of course that space fills up with other things.
Originally Posted by Mark Crabtree