I am guessing that a Garden Tub is a very large tub (please correct me if I am wrong). I have a whirlpool tub with 8 jets which uses more water compared to the average tub. I use at least 4 cups of Epsom Salts (any drugstore brand) and an entire bottle of hydrogen peroxide.
First buy a natural fiber skin brush and dry brush your entire body always brushing toward your heart, you need to open up those pores that are clogged.
Make sure the water is warm, not hot, you could put a thermometer in it and make sure the temp is not above 98 degrees. For beginners, hot water can make a person really sick. Also brush the bottoms of your feet.
During the bath (try to stay in about 20 minutes or longer) drink lots of filtered water with lemon juice so you won't get dehydrated. The epsom salts do several things, they draw out the toxins while absorbing magnesium which most sick people need lots of.. The hydrogen peroxide is adding extra oxygen into your blood stream which lyme bacteria hate.
If you feel strange after the first bath, that is normal and not to worry. Some people add an essential oil to to their baths, I light candles, love aroma therapy!
If you scroll down to the center of this page, you can read more about detoxing. I still drink Green Vibrance as it's a great immune boosting supplement. I buy it at the Vitamin Shoppe.
Hope this helps,