My Glycin is also light brown, but I've seen no loss of potency. I bought 100g from Monocrom last October, so I still have 09g or so to se if it changes with time. On a side note, my FX2 film developer was left in an open glass beaker for a week between uses with no ill effects. Given that I stand-developed the last batch for 90 minutes it would probably have worked anyway...