yo-yo fish-in cycling

[jdsunflower]

Hi,
Had a recent problem with my tank, and am starting over cycling, this time need to do it with fish in (5 surviving corys). I have no plants at this time but will acquire some ASAP as I really like how it cycles the tank very gently....
Two questions:
One: What is the impact on cycling (and especially nitrite levels) when the tap water ammonia level is higher than the tank's--partial water changes to keep nitrites below .25 (can't seem to bring it any lower than a smidgen below .25 despite about 1/3 water changes daily and tap nitrites 0) keep bumping up the ammonia levels. Currently, ammonia in the tank has gone down below .25, but from the tap it is around .5 after dechlorinator.
Two: What is the acceptable level of nitrites if I can't keep it at 0, 'tho I know 0 is ideal?
Thanks,
JD
ps: oxygen at 11, temp 80: 40B, Eheim outside canister with no fine filter. Bogwood, black flourite, fish currently on crushed anti-parasite fish food as only food, vacuuming anything left over to minimize impact on water.

 

[SpeedEuphoria]

Try to keep nitrite below 1.0

The other main questions are what size tank?, if its small then 5 cory's may be too much, I recommend that you take them back and try 1 fish like a danio to lessen the bioload.

Also why are you restarting the cycle? It seems your medicating the fish for some reason?

Your in a hard situation if you have ammonia in your tap water as some people say that dechlor( that locks up ammonia only lasts for 24hrs), however I have not looked into it and I dont think if you change a chemical composition that in 24hrs it just magically reverts back to its original state(like Cinderella). I think what that means is that it will lock up the current ammonia for good, but all the ammonia added by the bioload after 24hrs will not be locked up(duh).

 

[jdsunflower]

hi,
thanks for your quick reply. It's a 40G breeder tank, so I think 5 corys isn't terrible. I had nematodes in the tank and freaked and broke it down after losing 5 rasboras and a golden snail...
It seems like a big part of the solution will be to just load the tank with lots of plants as I had before, that should take care of the ammonia. I'm just worried that adding ammonia when the tank is cycling will mess with the usual rhythm...
The treatment is prophylactic in that after breaking down the tank the corys are still breathing fast, so I don't know if it's residual from the nematodes, or damage to the gills from the spike of ammonia I had before I broke the tank down...
sigh

 

[Purrbox]

Ideally you want to keep Ammonia and Nitrites under 0.5ppm, but under 1ppm is also acceptible if not ideal. Using Prime or another dechlorinator that treats Chloramine and Chlorine while detoxifying Ammonia and Nitrite would be a good option for reducing the effects of cycling on your fish.

 

[jdsunflower]

update

thanks for your suggestions, I've been using Big Al's dechlorinator product, but it sounds as though Prime is really quite superior.
I am managing to keep ammonia below .3 and nitrites around .25 with lots of PWC, but it is a terrible time to be without plants (meltdown).
I will buy today what I can in plants to (treat and) throw in there. It is sooo different and more challenging to cycle without plants. Never again!

 

[marchmaxima]

Prime or Amquel+ is a particular type of dechloronator that contains ingredients that will detoxify harmful Ammonia, however you will possibly still see an ammonia reading. However after being treated, the ammonia will be in a harmless state rather than a harmful one.

I don't have this problem, so I'm only going by what I have learned from others here, but my understanding is that if you have ammonia in your tap water, you need to use one of those two products that will convert it to a "safe" type of ammonia.