What are people's experience of the life span of an opened bottle of Aculux? The reputation of the Paterson developers is that they do not last long once opened but I am finding that Aculux is lasting a reasonable time (maybe this is different to experience with Acutol and FX-39). I have a bottle that has been opened now for 3 months and though the liquid has gone somewhat yellow (but it is still clear) the developer is working fine. I have kept the developer in the original red bottle and have not done anything fancy with marbles or inert gas. When I first started using Aculux the advice was that it it would only last a month at most. I think if it could last for this long it would be a great asset to the developer which, in my humble opinion, gives incredible tonality to negatives. But it would be nice to know if this is a one-off piece of luck or a more general experience.