Be careful if you rinse with water between Dev and Bleach as I find 'Chromogenic B&W Films' such as Ilford XP2 Super and the Fuji one ( Made by Ilford ) RETICULATE the backing coat badly and was told by Ilford Ltd NOT to rinse between Dev and Bleach.
Fresh Blix will gas out quite a bit. I only use enough volume to cover my reel to help control leakage. Is you're using SS tanks, and SS lids, switching to plastic lids will help contain it. I also leave the cap off of my lids between agitations to prevent leaks or the lid from coming off.