Alright guys I have been doing the reef thing for a good 5 to 6 yrs know so I know a good amount of stuff about keeping the tanks going but for some reason I just lost my firefish about a week ago and cant figure out for the life of me what happened to him,I diddnt notice anything wrong with him no tattered fins,he was eating fine and the just out of no where he disappeared I know that sometimes these guys will jump out of the tank but that didnt happen,maybe an internal parasite but that couldnt be it either because he was gaining weight and looked very healty,I have been adding some seachem reef builder for the last 2 weeks or so because my alkalinity is very low,and I was wondering if maybe this might have caused a problem but I dont see why because all the other fish are doing great still and are not showing any odd behavior this has happened before with my hippo that I had for 2yrs and she up and died so I just chalked it up as a loss,but after u lose another fish the same way it kinda gets a little agervating all params are fine salinity at 1.023,ph is at 8.3,nitrates at 0,gh 8,kh gets a colorchange at 5 to 6 drops,and calcium is low that is why I have been adding the reefbuilder to get the alkalinity right so I can build up my calcium level and the temp stays at 78degress, so if any of u guys can think of anything let me know.