Ok, my brother in law was speaking to a friend of his at work. For the past three years his friend has been using hydrogen peroxide to sanitize his tub. He told him that he has had zero issues with the tub and does not require any other chemicals.
I remember reading online before that this was not a good idea, however, my brother in law in convinced that this method is not recommended because it takes away sales from dealers on chemicals.
Can someone provide me with some info to go to him with. I currently have set him up with bromine and feel that this is the best method for him. His tub is used and he does not care about warranty issues, I already tried that approach with him.
This does come up from time to time and generally the answer is not to use hydrogen peroxide (H2O2). Hydrogen peroxide is more an oxidizer than a sanitizer and users will speak of the lightning strike smell of the water just as ozone users do. Also, biguanide systems use peroxide to shock or oxidize.
From what I understand, the real problem with hydrogen peroxide in a spa or pool is the abiltiy to measure accurately, the difficulty with delivery and transportation, the fact that it is not a registered sanitizer and the cost. To actively kill bacteria water needs to contain 40 - 50 ppm H2O2. A 500 gallon spa needs about one cup of 35% food or industrial grade peroxide to get to that level. A gallon of food grade peroxide costs about $100.00 and looses strength with time. Peroxide at that strength is dangerous to transport and dangerous to spill on your skin or in your eyes. It also reacts adversely with certain rubbers and plastics and most all spa manufacturers disallow its use. I seriously doubt peroxide is not used because it would take sales from spa dealers. If it were a good method of sanitation, dealers could and would sell it. The 3% peroxide you buy for your medicine cabinet will do virtualy nothing in your spa.
Accurate measurement seems to be another problem not only in the spa water but also in the manufacturing process. Apparently there are test strips to measure peroxide levels, but finding them will take a little effort. The pH of food grade peroxide tends to be on the acidic side at about 4. From what I can see, there aren't a lot of positives to using hydrogen peroxide.