Hey guys. I have just finished up my third batch of an IPA. The primary I have been using for these three batches has some small reddish/pinkish spots only on the bottom. I have tried to get these out with a bleach solution, oxy clean, and simple green but they just wont come out. What could this be? My beer has had a strange off flavor all three batches (different recipes from different homebrew stores and have switched to spring water, still there). Any way this could be causing it? I cant imagine how the stains could have gotten there. Any help is appreciated. Thanks!
P.S. - Tried to take pictures but the spots wouldn't show up.