How long do you think the peroxide and water mixture can be stored and still be effective? I know to keep it in a dark colored bottle(since it comes in one, duh), but I know I would not use all of it at one misting and I stagger my seed starting.
Since the stuff you get at the drugstore is already effectively a diluted solution, I would think you could dilute it further and hold it a while as long as you keep it in a dark bottle as you said... but I don't have a definite answer. I make up strong chamomile tea and keep it in the fridge, then dilute as needed...
I don't really mist my seedlings, but I use the peroxide when I water them when they're little... so I guess I go through the peroxide water a little faster.
I also figure I'm more likely to get into trouble with misting because then the foliage is wet -- to me, that seems like it could just invite fungal disease. Big greenhouse growers need to mist to keep humidity levels up, but I don't think we need misting on our little light shelves... at least, not misting works fine for me. :-)
(If you mist and that works for you -- keep doing it! Don't fix it if it isn't broken... there are lots of "right" ways to do things.)
I forgot to say what a great article. This year I am starting some pretty special seeds for myself and others. In the past I have never had a problem with damping off, but this year I have to be extra cautious.