Try reducing salt to 1-1/2 tsp in that liter of water and sip it throughout the day. Added to the liter of water with the borax, you need at least one more liter to truly get urine moving, plus any extra liquids you care to drink. That would total up to 4 liters of liquids. Too much salt and not enough water won't move bromine through the kidneys. If you're not smelling it in your urine, and not going to the bathroom several times a day, you may not be processing much bromine.
If you haven't tried oil-pulling, consider doing it. It's a powerful tool for my husband, including when he had the red bumps. He used organic sesame oil, about a tablespoon, and swished for 10-15 minutes. Then he spit it into the toilet. Occasionally the bromine stench would be so strong he would just about vomit. It's an additional tool for clearing this mess, but it doesn't work for me.