You are brushing your teeth with chlorous acid that has a PH of about 3. Acids in the mouth can effect tooth enamel.
Chlorous acid does bleach and it is used by dentists for whitening teeth, but they take special precautions when using it.
The solution that you have been using has about 800 PPM available chlorine dioxide. Dentists have found that 15 - 30 PPM works great for oral hygiene, and does not damage the teeth if it is PH balanced.