I built a 3 tap kegerator last December. I had 3 beers on tap this month and they all have a weird taste that I can’t put my finger on. Is it possible that if I had one keg contaminated, that they all could get contaminated. I bought my manifold online and am not sure if it had check valves on the out ports of the manifold. Right now I have all Co2 lines disconnected and will be replacing with better line. Are check valves necessary? Thanks for your replies.