Brookynella Hostillis is a disease caused by a protozoan. It affects only fish, not inverts. It is HIGHLY contagious and can kill rapidly. I lost 14 fishes in a row, all of them died within 48-72 hours of the first sign of symptoms. This was also despite my efforts at treatment, using rally, pimafix, melafix, 50% water changes, etc. Copper doesn't work. Seems like the only effective treatment is formalin(which is hard on the fish). Some literature indicates that freshwater baths help. Well, I finally got rid of the problem by making a 90% water change, refilled with real ocean water, added an UV light purifier and some carbon to remove last traces of medicines.
Only 2 fishes survived during the whole chaos, an adult formosa wrasse and a lunar wrasse, also all the snails and inverts.
IMHO, no fish tank should be running without an UV light purifier, all my other fishtanks have one and never had any problem with diseases.
And yes, they all run 24/7, no worries about killing beneficial bacteria. 90% of the beneficial bacteria lives on the rock, not in the water.
List of the fallen:
Blue and Yellow Damsel
(2)Cleaning Wrasses
Majestic Angel
(3)Porcupine Puffers
Australian Harlequin Tusk
Map Puffer
Christmas Islands Golden Puffer
Hawaiian Saddle Back Wrasse
(2)Clown Triggers
Fuzzy Dwarf Lion Fish
In my case, I got the infection due to heavily fouled water with rusted and rotten metal screws and clamps used by the guy who drilled my tank and set up all the plumbing and pumps.
This combined with extremely low water circulation, because the guy used a mag7 for a 98gal tank(used with 6 foot of tubing), water barely came out from the return line.
