Here is what Geoffrey Crawley wrote about FX-37 made up with 1g/L potassium bromide and no benzotriazole, taken from Amateur Photographer 15 Oct 2005:
"The only difference between this and the original FX-37 formula is the increase of potassium bromide from 0.5g to 1g and the consequent omission of benzotriazole,which is difficult to dissolve-a move to help the amateur.That chemical was originally included for the conditions of professional reuse as fog levels can rise.The change has no effect on image quality."