Brown blix could be a sign of carryover from the developer. If so, the pH has gone up too high (among other changes).

Try adding some 28% acetic acid very slowly to a small test sample. It should turn red again. If it does not, then it is truly bad. If it gets cloudy, it is truly bad, but if it is clear red, you are on the right track.

The pH should be 6.5.