It's one oz of 35% H202 to 11 oz of water.....so I get a gallon jug of pure, and take out 18 oz of water, and add 10 oz of H202.....isn't there 128 oz in a gallon? Anyway, that's how I do it, and then keep that jug of water, MARKED WELL in the garage fridge.
So you can use that 1 oz to 11 oz in your tub. But if you make three percent, then it doesn't matter how much you pour into the tub.
I don't know which worked, because I had my husband soak in a mixture of H202 and CS.
Does that make sense?
Oh yeah, we also bathe in H202, with Epsoms and Sea Salt and baking soda. But you never add the extra salt and other stuff when using CS.