That kind of sounds like my high range pH indicator, when it went bad. It turned a sickly brown yellow color. It wasn't pure bromythmol blue, well I think it had that in it, but had other ingredients too. Bottom line was it was outdated. Actually it was almost like the other ingredients were working, but the bromythmol blue wasn't, because when I would mix it with pure bromythmol blue it would actually give me a color on the chart that was plausible. Anyway I'm wondering how old the solution is in these cases.