this is the story...i do weekly water changes about 10 gallons every sunday...i went to clean my filter cuz it was due and my carbon bag ripped...ok i put a new 1 in and bam...water has bin cloudy for about 3 weeks now...2 of my koi died with my ****in baby red tail catfish...my red tailxtsn catfish...silver tip cf and oscar are fine...its a 55 gallon tank with a 70 gallon hang on bak filter....my tank u cant even see the other side...everything checks out ok...wuts going onnn!!! how do i clear it up?/// bacteria bloom??