Has My Aquarium Cycled?

[Ma84]

Hi everyone,

I've had fish in my aquarium for about 4 weeks now. I've used some old filter media and was told this may possibly (depending in the levels of bacteria) stop me seeing an ammonia and or Nitrite spike. As I was doing a fish in cycle (6 cherry barbs in a 120l) I was doing daily water changes for the first week and a half, by doing this I was never getting a reading for ammonia or nitrate so I started checking the levels everyday and just doing a pwc when there was an indication of ammonia. Ammonia has never got above 0.6mg/l and has now dropped off to 0, I've not recorded any Nitrite. My latest readings show 0 ammonia, 0 Nitrite, and a Nitrate reading below 5mg/l. (the nutrafin liquid test lot starts at 5 but the pink tinge on the test sample wasn't as dark as the colour on the chart). My PH is at 7.0. I've also noticed that a small amount of algae has started building up on the glass over the last few days.

Does this sound like the cycle has finished?

Would the use of old filter media explain the lack of Nitrite and low ammonia levels?

I have 4 java ferns (about 8 leaves 6 inches long each), 2 moss balls and use a juwel nitrate sponge, would all of this have a significant effect on reducing nitrate in a 120l tank with 6 small fish?

Any help/comments would be greatly appreciated.

Cheers,

Marc

 

[Jammiedodger]

It is possible the old filter media has helped the bacterial community appear.. and that would explain good water conditions.
If you haven't seen a bacterial bloom then usually it means a tank isn't matured but from what you've said I'd say it's about ready.

Maybe try just adding another few cherrys over the next 1-2 weeks and provided the water stays stable... voila! The tank is ready

 

[Ma84]

Thanks for your response. I'll try Adding a few more fish and keep an eye on it. The water was slightly cloudy for a week or 2, I assumed that was a bacteria bloom.

 

[Xraymark]

If after a week with no water changes and you are getting zero ammonia and nitrite then you are probably cycled for the fish you have in stock. Also you should see an increase in nitrates.

 

[OldMan47]

It sounds to me like you got a good filter clone Ma84.
Congrats. Just take the stocking process slowly and monitor chemistry as you go.