Will Temp Drop Kill Biofilter?

[mic209]

I run a permanent QT tank, when there is no fish in there I keep the filter full of bio media running, but I turn off the heater to save on the electric bill. It's in the garage so 2 weeks ago I moved the fish in it over to the display, turned the heater off and the water dropped down to 50-60 degrees for around a week and half. Last Wednesday I got my next batch of fish, so I turned the heater back on Tuesday. The tank has been cloudy since the day after I added the fish, 2 days after I fired the heater back up. I don't know if its a bacterial bloom or calcium precipitate. I've been doing 5 gallon daily water changes (tank is 20 gallons), running filter floss and carbon, but the water is still cloudy. What you guys think is going on?

[bertoni]

The temperature drop might kill some or a lot of the filtration bacteria, or the cloudiness might be from the decay of larger organisms that died. I'd watch the ammonia level. If that stays down, the tank probably will be safe enough.