Nitrite Spike In Fishless Cycling Tank

[dudleyd]

I thought i had finally come close to finishing my fisless cycle (using ammonia) that i started on november 23rd. Ammonia is being reduced to 0ppm in 12 hours (probably less and nitrite was also being reduced to about 0.25 in 12 hours and 0 in 24 hours. Now however (about 5 days ago) Nitrite has shot off the scale again and stayed there. Ammonia is still being reduced down to 0 from 4ppm in 12 hours.

Has something gone wrong or is this just a normal hiccup?


Cheers
DD

 

[waterdrop]

DD, I would just consider this the normal type of stray spike and is exactly the type thing we are guarding against by being watchful enough to get both down to zero in 12 hours and to do the qualifying week. Since you are way out at the end of the 3rd phase of fishless cycling though, I'd definately do a 90% (down to the gravel) gravel-clean-water-change and refill with conditioned, temp-matched tap water and recharge ammonia back up to 5ppm (and recharge baking soda if you are doing that.) It may take a couple days to get its numbers settled back down to something understandable after a big water change like that but hopefully you'd then find yourself ready for the qualifying week or alternatively that yes, you have some problem with your nitrite-processors and they need a little more build-up time.

Meanwhile, examine your stocking plan with an eye to whether any of the species will not be there (for instance, if neon tetras need to wait the obligatory 6 months from tank start or you want to wait for better water for the more expensive centerpiece fish or something like that) and if that's the case and you will be stocking only at 50 or 75% of the inch per US gallon guideline then you may be able to consider just skipping over the final "sticking problem" (where nitrite (or, rarely, ammonia) keeps showing a trace at 12 hours, but then goes away shortly thereafter. Sometimes in those cases we tell people to just go ahead and do the big water change and keep a watchful eye for spikes.

Does all that make sense?

~~waterdrop~~

 

[dudleyd]

All that makes perfect sense WD thankyou very much.

I put some bicarb in just to give the water a bit of a PH boost and now everything seems fine. Ammonia and Nitrite are now being processed down to 0 in 12 hours ,it's only taken 2 months to get to this stage. So a week of qualifying (assuming nothing else happens) and then time for fish.

It has however just occured to me that as i've been so interested in the cycling process I have no idea what fish to get.

So any ideas, i would ideally like some shoaling fish.

The tank dimensiones are 60cm wide, 25cm deep and 35cm tall.

My lfs is a pets@home so really need fish from there. And don't worry i'll be adding them gradually and not just dumping 20 fish in there.

Thanks
DD

 

[waterdrop]

Well, one of the reasons you fishless cycle is so that you can indeed safely do a large initial stocking of the tank. Its not necessary of course but the larger the initial stocking the more you are taking advantage of the work you've done by fishless cycling.

Are you familiar with the major questions you want to be working on to make a stocking list? One aspect is the overall capacity of the tank. For that we use the "inch guideline" which is extremely rough and has all sorts of things wrong with it but overall is still judged to be a good one for beginner success in the first year and half or so. In your tank you would estimate that 14 inches of fish body (fins don't count) for medium small torpedo shaped fish would be your max. For fish with larger bodies you total would need to be less than 14, whereas for fish with tiny bodies (like neon tetras for instance) you can have a few extra. There are all sorts of exceptions and problems but this general description should get you started.

The second aspect is species grouping. Many fish need minimum shoal numbers. For instance, many tetras need a minimum of about 6 fish to feel they are safe and thus to reduce stress on the individual fish. You have to kind of figure this out for each species but 6 is a good number if you can't figure out otherwise. Other grouping considerations are that some fish like to be in pairs. Some need certain male/female ratios. There are probably other grouping considerations I haven't mentioned.

The third aspect is interspecies relationships. Most of this consideration is about aggression. Each species you choose needs to be considered in relation to every other species you will have in the tank. There are issues of size, territoriality, nippyness, fin size, restlessness... that sort of thing.

These three major aspects of creating a stocking plan often keep interacting with each other. As you revise your plan to resolve one of the above issues, it may bring up a new issue in some other regard so you just have to keep refining.

~~waterdrop~~