Cycled!

[CletePurcel]

I set up a tank for tropical fish about a month ago and have been following the guidelines on here for fishless cycling. Today my NO2 dropped to zero all of a sudden . The tank is 100 litres.

Here are my numbers for the past few days:

15/9
NH3 1.00
NO2 off the chart
Ph7.2
added 2ml NH3

16/9
NH3 0.25
NO2 off the chart
pH7.2
added 2ml NH3

17/9
NH3 0.25
NO2 off the chart
pH7.2
added 2.5ml NH3

18/9
NH3 0.25
NO2 off the chart
Added 2ml NH3

19/9
NH3 0
NO2 off the chart
pH7.8
added 2ml NH3

20/9
ditto

21/9
ditto

22/9
ditto

23/9 (TODAY)
NH3 0
NO2 0
NO3 80
pH7.8

What is the best thing to do now?

I guess I should wait a few days to make sure the NH3 disappears within 12 hours before introducing fish.

Should I do a water change to get the nitrates down? Or wait until I decide I am properly cycled.

Is it safe now to start introducing plants?

Is the pH a bit high? Note that the pH readings have stayed at 7.8 since I started testing with an API master kit. The earlier lower readings were done with test strips so I suspect they were not accurate. My water from the tap is supposed to be 7.3 according to the water company.

Thanks.

 

[Katch]

Keep dosing 4-5ppm ammonia every 24 hours at the same time each day.

Test after 12 hours - you need zero ammonia and zero nitrite at 12 hours for a week to verify your tank is cycled.

I'd not worry about pH or water changes for now.

 

[toshapetriji]

Yes I would agree with katch on this. You are very close right now.

 

[CletePurcel]

Thanks. I'll just keep at it.

 

[waterdrop]

If this is the first drop of the nitrite(NO2) to zero ppm after the nitrite spike stage, then it probably dropped to zero about 24 hours after the last dose of ammonia. This is the beginning of the 3rd phase of fishless cycling and now your goal is for that nitrite to drop to zero within only 12 hours after the ammonia was dosed. During this phase you test twice a day at 12 hours and 24 hours. You only ever dose at your 24 hour mark though, and only if ammonia dropped to zero ppm within the previous 24 hours.

As the others said, this is good progress. You are at least 2/3 the way through now and possibly more, as sometimes the 3rd phase can move very fast. Once you achieve double-zeros at 12 hours you want to watch it do that for a week to be sure it does not fool you. Your higher pH is actually -better- for raising the bacteria.

~~waterdrop~~

 

[CletePurcel]

I am continuing with the fishless cycle, but now my ammonia levels seem to be harder to get down. The Nitrite is almost always zero.

Is it normal for the NH3 level which was going to zero every 24 hours (from 4ppm) to now take 2 to 2 1/2 days to go to zero?

 

[waterdrop]

Yes, we see this pretty often. It surprises people that the delay will switch back to being the ammonia instead of the nitrite but it happens like this sometimes in the 3rd phase. Make sure your pH hasn't crashed (it can happen suddenly because of all the nitrate being produced.) If it keeps being stubborn I recommend full water changes on the weekends with ammonia recharge.

~~waterdrop~~

 

[CletePurcel]

Yes, we see this pretty often. It surprises people that the delay will switch back to being the ammonia instead of the nitrite but it happens like this sometimes in the 3rd phase. Make sure your pH hasn't crashed (it can happen suddenly because of all the nitrate being produced.) If it keeps being stubborn I recommend full water changes on the weekends with ammonia recharge.

~~waterdrop~~

pH is still at 7.8. Things seem to be moving again now.