Think I Killed My Filters Bacteria?

[Spishkey]

didnt realise the heater in my oscars tank was not plugged in, also the rooms heating is not working so for the past few days the water must have dropped in temp. got up today the oscars and crayfish were all sulking and the room had the most horrible stench to it. opened up the tank immediatly the smell worsened, firstly thought something had died in there but all fish and crayfish accounted for. water was very cold for that tank.
pulled the lid off the filter, oh my god the smell. im guessing the cold water has killed off the bacteria?? would it smell so bad? i cant think what else it could be?

how is the best way to go about fixing this?

i have only small tanks i could 'borrow' media from but it wont be anywhere near enough. i have another 500L tank but dont dare touch the media from this as it is a very well balanced tank with new additions and i f that goes into a minicyclen a lot of the fish wont make it.

am i resigned to daily water changes until it recycles or is it likely not to be the bacteria? water stats are currently ammonia 0 nitrite 0 nitrate 50 (normally 5-10) have performed a 50% water change to hopefully bring this down?

 

[minxfishy]

Dont know what would be causing the bad smell, other than something rotting inside the filter, but the cooler temps shouldnt have damaged the bacteria, really really cold water could affect it, but I doubt the tank water got much below 18c or so and thats normal temp in sub-tropical tanks and even cooler in cold water tanks all of which have bacteria to keep them healthy.

 

[petertr]

Get the heaters working
Do a 50% water change, then another one 4 hours or so later

Check the tank & filter(s) for anything dead

Next day, check for ammonia or nitrite. If its there, you may be going through a minicycle. If its bad, you can always borrow 25% of the media from your other 2 filters without hurting them.