A short search found this, but I'm sure there's more...
http://www.truhealth.com/July2006-HealthyHotTubs.htm
HEALTHY HOT TUBS
Summer is here and nothing is more relaxing than sitting in your hot tub at night looking at the stars and moon. But how healthy is it to sit in a hot tub?
Let’s see we have tap water, which has chlorine, and fluoride in it already, and then either chlorine or bromine as the most popular cleaners and then additional chemicals and fragrances.
So to start off with, chlorine isn’t the healthiest thing to be sitting in. Chlorine is commonly found in nature, but almost always in combination with other natural building block elements. Every time you drink a glass of tap water, read a newspaper, put on a vinyl raincoat, brush your teeth, drink a diet cola with Splenda®, or drive your car, you are using chlorine in some form.
Chlorine vapors can irritate your lungs and pose a serious risk to people who suffer from lung problems. This is especially true for people suffering from heart conditions or chronic respiratory problems such as asthma or emphysema. Chlorine is also a highly corrosive substance capable of damaging the skin, eyes, and other delicate membranes. Remember how your eyes burn after swimming in a highly chlorinated pool of water?
Pregnant women in their first trimester who drink five or more glasses of chlorinated tap water a day may be at a much higher risk of miscarriage than women who drink non-chlorinated water.
Ok – so what you may not know is that chlorine (and fluoride) pull iodine out of our bodies. So you may think this is no big deal, but iodine deficiency is a huge problem in this country. The thyroid controls our body metabolism. The thyroid also affects our sinuses, lungs, kidneys and the lymphatic system. Sitting in chlorinated water can only make this worse. In addition, iodine is a well-known cancer preventative. Viruses, which cause many cancers, cannot live in an iodine environment. So taking iodine out of our bodies just cannot be a good thing!
Many people think that if they use bromine (also called bromide) instead of chlorine that this is a healthier option. But actually, bromines are even worse than chlorine and are finding their way into our environment in ever increasing quantities. This is noticeable by the fact that the amount of bromine found in breast milk has increased ten-fold over the last decade. There is no positive affect from bromide, but instead it also affects the absorption of iodine in our bodies. (Iodine: Why You Need It Why You Can't Live Without It, M.D. David Brownstein)
For the chemistry behind this - there is this well-known chemical law, called the law of halogen displacement. The halogen group is made up of: Fluorine, Chlorine, Bromine and Iodine. Respectively their Atomic Weights are: 19, 35.5, 80, and 127. The clinical activity of any one of these four halogens is in inverse proportion to its atomic weight. This means that any one of the four can displace the element with a higher atomic weight. Since Iodine has the higher atomic weight it is constantly at risk of being removed from our thyroid, especially if we drink chlorinated water. (Folk Medicine, DC Jarvis, 1958, pg.138)
CREATING A HEALTHY HOT TUB
Don’t get rid of your hot tub just yet – there are many healthy options.
First of all, once you fill your hot tub with clean water, use a filter to remove the fluoride and the chlorine or pour in a product you can purchase at greenhouse or hot-tub stores that does this. Once you remove these harmful elements. You still need to keep the water clean. The key to this is the pH.
The pH is “the potential of Hydrogen”, which is a measure of the acidity or alkalinity of a solution. The lower the pH number, the more acidic the solution is, the higher the number, the more alkaline the solution is.
PH is pH, is pH. It doesn’t matter whether you are testing your pool, your body, or your fish tank. The scale is all the same. The problem is that the hot tub people have “idiot proofed” their chemicals – so if you see one color, you know what product to pour in when. This way you have to purchase their strips, and their product. (This is called smart marketing on their part J)
But with a little common sense you can figure this out yourself. Know that the pH of the water in your hot tub should optimally be between 7.2 and 7.6. Purchase some pH strips that show you the actual numbers, not which product to use per color. You can get these in health food stores, pet stores, and sometimes in hot tub/pool stores.
If your pH is too acidic, you will need to alkalize it. Baking soda is a great alkalizer. If it is too alkaline, you will need to add something acidic. Food Grade Hydrogen Peroxide (which can be purchased in many health food stores) is a good choice here. Some people I know add 1 cup of Hydrogen Peroxide every week and use nothing else to sanitize their hot tub. Hydrogen peroxide is one of the most powerful oxidizers known -- stronger than chlorine actually. And it is also an effective bacteria killer, but much safer for people.
Another option is essential oils. A family I know has an outdoor hot tub for 9. They keep their hot tub disinfected using just essential oils. The recipe they use is 18 drops of geranium, 5 drops of lemon, and 3 drops of lavender. These are all medicinal grade essential oils – not the inexpensive perfume oils.
Essential oils keep the water clean and sweet smelling for about 2 weeks, although they do change it more frequently after birthday parties, etc. The original recipe called for 3 drops of Tea Tree oil, but enough people have skin sensitivities to it that they substituted the lavender. It works extremely well, leaves no residue in the filter, and did not interfere with any of the plumbing. Be sure to always add the oils directly into the center of the water, not directly into the filter. They have never have had an incident of illness or rash that could be attributed to our hot tub. I have heard that some people also use this recipe when they want to go away for a few weeks, and that the water was always fresh and clean when they returned home.
Other people disinfect their hot tub very effectively with homemade colloidal silver. To do this, you will need a machine that makes this for you. Here is one website that offers the necessary items to do this.
http://colloidalsilverresearch.com/coll50.htm
Another option is to use an ozonater. Ozonators can be purchased at most spa or pool retail locations. However, they typically tell consumers that they also need to use chlorine/bromine in addition to the ozonator. This might also be depending on the type of ozonator used. Here is one website that sells ozonators that states that no additional chemicals are needed.
http://www.rhtubs.com/ozonator.htm
Miracle II neutralizer is another product that I have heard from people that they use in their hot tub to keep it clean. To learn more about that do a Yahoo or Google search on Miracle II and there are lots of people who sell it and can give you more specific information on that.
Another product that has actually been on the market for nearly 20 years is a seaweed based cleaner. This specific seaweed was used for centuries by Roman Emperors in their golden spas, by Kings and Queens of Europe, by world famous spas, and is now available to you. You can learn more about this product at
http://www.spamagicusa.com/1137150.html.
As with any of these cleaners, once you put them in – be sure to take the pH of your water weekly to make sure your keep the pH of your tub where you want it. After you add something to make a change, let your hot tub cycle through a water flush and then take the pH again to make sure you are getting the desired results. You can keep adding little by little of items to make sure you are moving the pH in the direct you need.
So have a great summer in your hot tub –after you make it a healthy place to be. Your body will thank you for it!
Sidebar
In the 1960’s, bakers stopped using iodine as a dough conditioner and started using bromides instead. So instead of contributing to iodine intake, breads made from brominated flour now help rob iodine from the body. Since iodine is needed to make thyroxin, the hormone that triggers fat to burn in the body, is it any wonder that the increase is exposure to these iodine robbers has paralleled an increase in obesity?
(Sunshine Sharing, Vol. 17 No.1)