Help With Fish Tank Cycle Please

It took 28 days for my ammonia to drop. If it wasn't for the fact that I already had three tanks running I would have got very frustrated (it was a sponge filter to replace the internal in my betta's tank and I cycled it in the quarantine tank).

Is it possible to take a bit of actual media from your small tank and put that inside the bigger tank's filter? It is safe to take up a third of the media from an established filter, though it is wise to keep an eye on the ammonia & nitrite in that tank for a few days.
The water from the small tank would have had virtually no filter bacteria in it because they are attached to surfaces not free floating. But the bacteria are attached to filter media, which is why using media works better.

This is the data I recorded for the fishless cycle I did in Jan 2016

Because this tank is 26 litres and has just one male betta and one small nerite snail, I initially added ammonia to just 1 to 2 ppm as this is more than enough for that bioload. The colour was between 1 and 2.


Day 1 - added ammonia Stage #1
Day 4 - no change
Day 7 - no change
Day 10 - no change
Day 13 - no change
Day 16 - ammonia still same but just a hint of nitrite though still well below 0.25
Day 19 - same as day 16
Day 21 - ammonia still showing between 1 and 2 and nitrite the merest hint. Got frustrated and did a 100% water change then added ammonia to give a reading between 2 and 4 ppm.
Day 24 - ammonia between 1 and 2, nitrite 0. The ammonia dropped from 2 - 4 to 1 -2 but no idea where it went.
Day 26 - tested after 2 days because getting fed up. Ammonia 1 to 2. Nitrite merest hint.
Day 28 - ammonia 0.5 nitrite > 5 (off the top of the chart). Added ammonia to ~ 3ppm Stage #6
Day 30 - ammonia 0, nitrite >5
Day 32 - ammonia 0, nitrite >5. Zero ammonia on 2 test 2 days apart, added the one third dose of ammonia. Stage #8
Day 34 - ammonia 0, nitrite >5
Day 36 - ammonia 0, nitrite >5. Zero ammonia in 2 tests 2 day apart, added the one third dose of ammonia Stage #8 again
Day 38 - ammonia 0, nitrite >5
Day 40 - ammonia 0, nitrite >5. Zero ammonia on 2 tests 2 days apart, added a one third dose of ammonia. Stage #8 again
Day 42 - ammonia 0, nitrite 0. Added a 2 to 4 ppm dose ammonia Stage #10
Day 43 - ammonia 0.25, nitrite 1.0
Day 44 - ammonia 0, nitrite 0. Added 2 to 4 ppm ammonia. Stage #10 again Then power went off for 4 hours.
Day 45 - ammonia 0, nitrite 2 - was the cycle affected by the power cut?
Day 46 - ammonia 0, nitrite 0. Added ammonia to 2 to 4 ppm Stage #10 again
Day 47 - ammonia 0, nitrite between 0.5 and 1. Added ammonia to between 2 and 4 ppm Stage #10 yet again
Day 48 - ammonia 0, nitrite 0. Finally stage #14

Ammonia and nitrite both zero 24 hours after adding full dose ammonia = cycle finished.



As you can see, ammonia finally dropped on day 28. And nitrite dropped from off the top of the chart to zero between days 40 and 42.

38 days into cycle no change, ammonia still 3ppm ,nitrite 0 ,nitrates same as tap water 10ppm ,chlorines 0
Still concerned , are some of the artificial plants and ornaments affecting the cycle ?
Have added another dose of water conditioner for 120ltrs to the tank.
I am going to add a bag of bio max from my 23ltr cycled tank to try and kick start , have three bags of bio rings and af isponge in small tank ,so one bag less ,is less than 1/3 of bio filter as advised by @Sue .
Still concerened about plants etc .Has any one else had any problems with artificial decor and cycling ?

ps Happy christmas all

ok thanks Matt. 

As far as I'm aware, there are only two 'bottled bacteria' products that contain the correct species of nitrite eating bacteria - Dr Tim's One & Only (very hard to get outside the USA) and Tetra Safe Start.
At first it was thought that the nitrite eaters were the same species found in waste treatment works (Nitrobacter), then Dr Tim Hovanec, working for an American company which has since been taken over by Tetra, discovered the correct species which grows in aquaria (Nitrospira). The use of this species was copyrighted or whatever the correct term is so that only he and Tetra can make a bottled bacteria containing this species.

Most other products do contain the right ammonia eaters, just the wrong nitrite eaters.

It could still be worth trying a different brand of bottled bacteria, it should help kick start the ammonia eaters.
The correct species of nitrite eaters function at the low concentrations found in tank, but the wrong ones need higher concentrations of nitrite. These bacteria will help during cycling where the amount of nitrite is high compared to in a cycled tank, but will die off as the level drops, something to bear in mind when interpreting test results.




If anyone knows of any other product which contains Nitrospira rather than Nitrobacter, please let us know.

Hi @Paddy60

Sorry to hear that you are still having problems with your 120L tank.
I would have thought that the bag of biomax from the small tank would have helped. Have you put them in to your filter - that will help the bacteria on the biomax grow into your filter media.
Have you had any problems with your pH? Just a wild shot but thought I'd ask because a drop in pH can cause a cycle to crash.

I'm no @Sue  when it comes to cycling tanks, and my experience has generally been with having a lot of mature media available from several tanks to be able to move into a new tank, so any cycling I deal with tends to have had a very big kick start. It has been over a year since I've had to cycle a tank "properly" rather than just moving mature media around. I've not used products like Bio Boost or Safe Start, so can't comment on them.

If it is any help then I am more than happy to send you a larger amount of mature media to help you with your tank. It may have to wait until the new year as I can't imagine what the postal service would be like until then, but it might be worth a go.

The biomax should have done something.


Is there any possibility something is in the tank that shouldn't be? You've used dechlorinator - which one? - so there shouldn't be any chlorine in there.
Did you use anything to clean the tank before starting the cycle? Any trace of a cleaner could do harm.
Are the two tanks in the same room? If the 23 litre is OK and they are in the same room, there shouldn't be any air born pollutant getting in the 120. If they are in different room, check for aerosols or air fresheners of any type.
And just to be sure, you do have pure ammonia not ammonia with detergent added?

am using kleenoff ammonia

ok have 4 ornaments and quite a few plants all but two ornaments where bought at maidenhead aquatics.The two ornament where bought on line one is a bridge ,and from china it looks like its made of resin but the bridge ropes are made of some other plastic. I have removed both now, will try this ,if this does not work i will strip all decor out and try that

Now you've removed the 2 bits of suspect decor I would do a large water change and re add ammonia to reach 3ppm. This will mean that whatever is in the tank from the decor you removed is also removed if this is the issue.  Either way it reduces the possibility of this being a factor going forwards