Often, a
bedikah that is ruled acceptable will start off with a pinkish tinge when wet. Incandescent lights often add a pink tint to stains. Rabbis are trained in taking this effect into account. Additionally – although a woman's assertion that a cloth was originally a
niddah color is believed by her rabbi – if she is not absolutely positive, the practice is to disregard her comment in favor of what is before his eyes. Therefore, we think that in most cases you should feel comfortable relying on your rabbi's statement that the same color need not be shown again.
If you are still concerned, we suggest that you should meet with the rabbi who has been evaluating your cloths and explain your concerns. He may suggest reducing the number of
bedikot, and should be able to help you find a way to proceed with which you will be more comfortable.