Tank Cycling, Water Changes And Effect On Ammonia/nitrite/nitrate

[backtotropical]

May I add that in addition to the Biofilm theory (which I believe to be absolutely correct in terms of food for certain fish and for water quality issues), that a newly cycled tank has a large enough bacteria population to deal with the ammonia and nitrite being produced in the tank, but the colony is quite fragile at this point.

As an example, I wouldn't recommend washing filter media in tap water for a newly cycled tank as it may severely damage the bacteria population, however in a 'mature' tank, I would say the bacteria would most likely be more than able to deal with it, and it probably wouldn't do much harm at all.

This in itself gives another difference between newly cycled and mature tanks, in that a mature tank is less likely to have a sudden ammonia spike due to a problem with the bacteria, as they seem to be much more robust as time goes by.

Going back to Biofilm, there are many many chemical reactions going on in a new tank, far more than the few we are able to test for, and it is thought that as the different bacteria etc become established in the biofilm, these reactions settle down, leaving a 'mature' tank with a much more stable environment for fish than a new one.

Hope that helps some.

BTT

 

[OldMan47]

I would add to the cargo cult theory. I find that I can often ignore the advice about certain fish requiring a better established tank but the theory about the fish keeper's skill also makes sense when I read all of the trouble that new fish keepers have with the "sensitive" fish. In the newbie section, I will continue to tell people to wait until their fish tanks are well established before exposing sensitive fish to the vagaries of a new tank. Another theory that holds some promise is the idea that we really have a one dimensional view of our tank's water. That leads to the obvious question of what is happening outside the nitrogen cycle that we do not monitor. One of those factors may be why the "well established" tank is a better choice for those fish. If I knew the real answer here, I would write a book on the subject and be able to retire.

 

[waterdrop]

Sometimes I wonder if it'll turn out to be dissolved organic carbons (DOCs) that will turn out to need more time to build up and will play some sort of role.

On the non-scientific side, I've always felt that there comes a day, often somewhere out there perhaps around the 6 month time period when one day I look at my tank and it has somehow changed from a bit of a "new" look to a definite "mature" look. I don't know what this is but it feels real to me, kind of like the light and water had a bit of a white-ish feel, whereas now the water seems exceedingly clear and the tank has a tiny bit yellowyer feel. I've had other aquarists agree with this feeling and I'd be interested if any of you have ever had that thought. Perhaps its just a bit of algae on the substrate reflecting the light differently, I don't know, but I often feel its accompanied with fish seeming completely settled and now at their peak in some way compared to earlier.

~~waterdrop~~

 

[alanbur]

Well, I'm now 20 days in, Ammonia & Nitrite both at zero and all the fish seem to be happy and healthy - fingers crossed!