Sorry for all your problems if it is septeicemia it's very hard to cure, how are the rest of the fish doing, as the whitespot gone, and have they any red streaks or patches on there bodies.
the white spot seems like its got worse ive uped the temp treated apprantly tommrow it should look better i just feel like theres hould be something i could do the sharks all dead except for one he only has red fins and nowhere else he is the worst affected by the white spot hes covered even my angels have it now