There are right ways and wrong ways to use Metro, or any medication for that matter. Not bumping up the temperature to at least 92 is the reason why you have this "ongoing battle" such as your title suggests. All you did was create a more resistent strain of Heximita that won't be effected by addition of Metro in the near future.Dosing 3 times per day is probably overkill, though hobbyists still do it. I dose 400-500mg per 10g once an day and do water up to 50% water changes everyday before I dose. You say that it is less effective at higher temperature, but consider the fact that women with vaginal infections take metronidazole in smaller concentrations once per day with success. The human body has a normal temperature between 98.5-99 degrees, several degrees higher than the temperature I suggested be the minimum.You're probably also aware that Metro at higher temps are ineffective as the 1/2 life of the med is expended too quick. My treatment is based on research that supports effective results. Raising the temp could also increase the chances of bacterial infection as the Hex dies off inside the fish, causing yet another problem, requiring more meds. My treatment was not an aggressive one, so I found it no need for changing the temp.
Please clue me in as to how dead Heximita is going to cause another infection. I'm curious to hear how this would work. Is it magic perhaps?