Well, on the acid side, Ammonium Ferric EDTA turns orange in solution and if the acid is strong enough, the Ammonium Ferric EDTA will precipitate as an orange brown solid forming a cloudy blix. Enough acid will also cause sulfurization, and that will form a cloudy orange blix. Actually, Ammonium Ferric EDTA powder is brown-yellow.

The correct blix color is a beet red or blood red color, so brown is bad. I must admit that the OP was a bit ambiguous, and I misread it to imply that the used blix was brown.

In any event, a brown color indicates a problem.

To test it, you can fog and develop a piece of B&W paper, then wash and then use the blix. The B&W paper should turn white! It should do so it less than 3 minutes at 20 deg C. If it does not, then lets talk about what did happen. And, if you can, look for cloudiness and check the pH.

PE