Am I cycled?

[AusC]

Hi All,

After a long absence from having a tank I’ve gotten keen to get back into things and am in the process of setting up my old 6x2x2 again. I’ve shouted myself an Ehiem 2080 Pro 3 1200XL and filled it with the factory pre filter, 4 L of medium grade then fine foam followed by 8 L of matrix. I’ve been working through a fishless cycle and I think its completed but would like to run my data past others. Essentially NO2 spiked to 2-5 ppm nine days ago and has been zero ever since. NO3 has been climbing steadily and is in the hard to read >30 ppm range. I have some lingering low level NH4 but wonder if it is due to the reliability of my test kit at low levels (new in date API freshwater master). Plenty of data below if anyone is keen.

Cheers

Craig

9 days prior to serious cycling half media filtering tank spiked to 4 ppm NH4, half media sitting in sump of friends cycled tank.

Day 1 (10 overall)

First day of serious measured cycling. All media into canister. Mulm from friends cycled tank also added.

Tap NH4 NO2 NO3 all zero

Tank spiked to 2 ppm NH4

Day 5 (14 overall)

Tank spiked to 2 ppm NH4

Day 12 (21 overall)

NH4 0.25 NO2 2-5 NO3 20-40

Tank spiked to 2 ppm NH4

Day 14 (23 overall)

NH4 0.25 NO2 0 NO3 40

Tank spiked to 2 ppm NH4

Day 18 (27 overall)

NH4 0.5-1 NO2 0

Day 21 (30 overall)

NH4 0.5-1 NO2 0 NO3 20-40+

 

[Raynado]

Apart from the 0.5 it looks to be cycled or just about cycled. Safe enough for me to add a fish and slowly add more. Happy fish keeping and welcome back to the hobby

 

[Yoimbrian]

I'd say no. Want that ammonia at 0.

If you don't trust your kit, get a new one.

Better safe than sorry...

 

[pops]

unless you are reading 0 ammonia. 0 nitrite, and some nitrate. tank is not fully cycled.

 

[Drstrangelove]

I assume that you are dosing at the same time each day, then testing some time a few hours later, but just in case...

Try taking ammonia readings at different times following the tank dosing. My expectation is it will decline from right after you dose. It should reach zero after a number of hours, although I can't tell you exactly when.

If it's not zero after a reasonably long time (e.g., 2-3 hours), it's not fully cycled. Although fish in an aquarium appear to create ammonia all the time (and don't create it all at once as a manual 'dosing' does), there is a peak that occurs from 2-6 hours after feeding that the BB need to handle easily. If the tank can't handle a peak of that sort, it needs more time to build BB.

It's better to do that of course rather than let the fish suffer gill damage from ammonia.

Of course the test kit might be in error, so there's that consideration too.

 

[AusC]

Thanks everyone for the feedback.
I found some more literature that indicated if KH gets too low a cycle can stall. Initial KH was 3 deg out of the tap with a tank pH of 7.4 so not much room to move. I tested again tonight and along with lingering low NH4 found a KH of 0 (turned yellow with first drop) and a pH of 6.4! So I think its safe to conclude I've had a pH crash due to low carbonate and have a stalled cycle. I'll buffer back up to a pH closer to 8 and see what happens.

Cheers
Craig

 

[AusC]

So another four days after buffering back to pH 8.4 with KH 7 and NH4 is now zero and NO2 has stayed zero. Interestingly pH has dropped back to 8.2 over the four days so might have to consider using a true buffer rather than just a hardness raiser.

I've spiked NH4 up to 4 ppm and will test again tomorrow night but this time I think I'm cycled.

Cheers
Craig