Not sure where this fits but heres my cautionary story. Had my 35 gallon hex running very good for well over a year. Went to bed one night, woke up the next morning and my fish died. One sole survivor was a goby. Didnt add anything to the tank, kept up with the cleanings. Very odd. My clowns were almost 3 years old so it was very disappointing to say the least. After the crash i checked the water and had my local shop check it also. No issues water wise. Guess something caused a tank crash....just not sure what.