I've worked with ABC pyro to get it to work the way I want it to but part of that includes adding a pinch of EDTA per liter of working solution. A pinch is probably accurate enough but it would still be nice to standardize and not worry. What I'd like to know is if it would cause any problem if stored in the A solution. The B solutions gets made from scratch each time so it's either A or C. Hoping that someone who knows about such things could put my mind at ease before I mix up a batch and accidentally let it sit for a month only to be underwhelmed the next time it gets used.