5 Day Old, 38G Tank...Cycled? O_O

[Zhoo]

I recently set up my new 38 US gallon tank after the original one cracked. I have had an emperor filter (for up to 55G) with established media inside running since day 1, and also on day 1 I added a packet of septo bac (strained) after adding 5 small fish...my water readings as of today - 0 ammonia and nitrites, 20 nitrates. I tested for ammonia daily and it's been at 0 since day one. I'm confused. It couldn't have happened this fast, could it?

 

[loraxchick]

if you used all old media from the old tank (assuming it was switched over in a fairly quick amount of time) then sure, its cycled. keep testing for a week to be sure but that is not unusual when swapping media between filters while maintaining the same bioload.
cheers

 

[Zhoo]

I transferred a whole filter from a different mature tank, media and all. I just thought i had to wait until bacteria colonizes the insides of the tank - gravel, plants etc. So cycling a tank is essentially cycling the filter, right?

 

[loraxchick]

I transferred a whole filter from a different mature tank, media and all. I just thought i had to wait until bacteria colonizes the insides of the tank - gravel, plants etc. So cycling a tank is essentially cycling the filter, right?

while the gravel,decor,plants etc do build up bacterial colonies, they are most robust in the filter and is where the vast majority of ammoina conversion takes place. so by switching the filter over and keeping the same bioload, the bacterial colonies are already large enough to handle the fish waste.
cheers