I never used more than the suggested dose but I treated enough times to kill a horse. I always left my skimmer and turf scrubber running in between doses, so likely much of was removed during the treatment.
My fish got sick the first time I treated it in my old 170. But that was not exit. And mentioned they got sick from either eating flatworms or just the toxin in the water from them dying. This was before we knew they were toxic while dying and siphoning as many out before treatment would help.
Most of the sick fish recovered, but I lost a couple chromis and one of my mated pair of orange skunk clowns. One of my cinnamon clowns, had serious eye trouble from it, but recovered and now, several years later is an egg laying machine.
