Cycled tank, added axolotl, nitrites spiked...

[CAH]

I've kept medium to large fish tanks for more than 20 years, and one simple axolotl has me flustered beyond belief. I started cycling a 20 gallon long before I ordered my axolotl. Tank had 9 zera danios, 5 diamond tetras and a young female blue acara. She was shipped and received almost a month after I started cycling. Tank wasn't finished cycling, so I tubbed her.. She'd been tubbed for another almost 2 monrhs, while the tank cycled. Finished cycle, removed heater, moved fish to other tank, let tank hit room temp, and then turned on a fan to get temp down to 63 (which is the temp of her tubs). Added her. The next day, there was a slight indication of nitrites (less than ..25). Dosed Prime. The next day, tank was at .50 for nitrites (ammonia still 0, ph 7.6, nitrates less than 10 but more than 5). Did a 6 gallon water change. Numbers stayed exactly the same. Fast forward to this morning.. Tested the tank, and it looks like a mardi gras party. Everything perfect, except that one sketchy guest - nitrite - which is still 1ppm. Did another water change just a bit ago - it's down to .50ppm. SHE is no worse for the wear - looks great, eats like a champ...

At this point, I'm assuming her poop is more concentrated than the 14 fish that preceded her. Do you think it will catch up, or do I need to retub, and start over from the beginning? I can do as many water changes as necessary - right now I'm doing about every other day. (and calling her a girl is wishful thinking on my part - I still don't know for sure. ) If you made it this far, thank you! LOL.

20 gallon Long
Set up May 20th
Fluval U3 internal filter
Aquarium Coop 20g sponge filter
Ammonia: 0
Nitrite: .25-1.0
Nitrate 10ish
PH 7.6

 

[wolfen]

axolotl tanks need to be cycled by using a high level of ammonia ie.. 4ppm, this is equivalent to an over stocked fish tank (imagine having an oscar in a twenty gallon tank) , this is because an adult axolotl can produce up to 4ppm per day in waste.
this means that the filtration has to house two types of bacteria to cope with the ammonia and the nitrites, right now you have enough bacteria to cope with the ammonia but not the nitrites.
unlike ammonia which is caustic and therefore noticeable at high levels due to damage done nitrites effect the blood reducing the amount of oxygen being carried slowly poisoning it.
use 2g/l uniodised salt or 50% holfreters + magnesium sulphate (a modified holtfreters) to reduce and protect against elevated nitrogen compounds, info here.. Axolotls - Requirements & Water Conditions in Captivity
assuming the filter and therefore the bio-media is large enough it will take time but should eventually correct itself if cycled properly for an axolotl tank, at the moment though you are putting your axolotl at risk.
tub your axolotl in cold dechlorinated water with either 2g/l uniodised salt or modified holtfreters changing water daily and giving daily 10min half fish dose methyline blue baths to correct and damage/poisoning done by the nitrites.