It is my recollection that it takes 3% H2O2 to use as a disinfectant (ie. kill bacteria) - I would thin you can use 3% to freshen your hose (so to speak)I didn't test sterilization levels, that would take a MUCH larger project (I did this one during my lunch hours). The reason is that there are a variety of organisms, all with different levels of sterilization. The worst IMO would be Neobenedenia fluke eggs, I bet you'd need to use 500+ ppm to kill them. I think general bacteria would controlled by 25 ppm.
I've toyed with the idea of using peroxide to freshen the water tank on my boat and camper, but again, without experimentation, I can't know the dose. I like it better than bleach though...
In the absence of bio-catalysts (algae) peroxide seems stable over a good period of time. If the water vessel were closed, there would be little re-inoculation during storage. I don't think a platinum catalyst would work fast enough to destroy the excess peroxide prior to use though. Sodium thiosulfate would work, (and you can use a DPD chlorine test to ensure you've added enough) but the chemistry of that compound is a bit complicated, and I always worry about using it in water for a reef tank.
Jay