Actually pharmaceutical hydrogen peroxide is not sufficiently pure to be soaking in so frequently. It is not FDA approved for that use, and for good reason.
Food grade hydrogen peroxide is the only grade approved for internal use. If you buy it in bulk it is actually the same price as the pharma grade you get at the grocery store.
It's 35% H2O2, as opposed to just 3% like the store bought stuff, so you need way less of it. One 8oz cup treats a standard sized tub full of water.
I get mine at this place. Buy two gallons at a time to get the best value.