hi please help, i have been keeping cichlids for about five years with no problems, now all of a sudden my firemouth broke out in big white spots on his fins, also my severum has velvet disease, put methylene blue in tank this evening and as i never used this before was unaware it would kill the bacteria in tank, how and when should i get rid of the blue water, also should i replace sponges in filter im panicking now incase ive done more harm than good please help