Question about F-24 formula

[steve goldstein]

Formula #138 for Kodak F-24 fixer suggests that "substituting 22.0 grams of Citric acid for the (25.0 grams of) Sodium bisulfite will largely eliminate the fixer odor. Is this really correct? I tried it yesterday and got a really nasty surprise - I think it evolved Sulfur dioxide, which was quite unpleasant in my small and poorly ventilated work space.