Nitrite rise question

Is it possible in a CYCLED tank to suddenly read Nitrites without reading Ammonia first....

And if so what would cause this typically?

I'm not exactly certain what you're asking.

One of the problems in all of this stuff is the word 'cycled'.....I personally don't like the word I(but have to use it) as it is misleading and not particularly correct (in the scientific sense and in everyday language sense).

I very much doubt that many tanks are ever fully 'cycled' to be honest.

The process of nitrogen fixation to ammonification to nitrosofication to nitrification and denitrification is not a linear path and is not a single direction, and has off-shots leading to other paths.

When testing water, there are many things that you could find.

Firstly, the test kits may not be accurate or sensitive enough (and afterall, the standard kits are only cheap assays anyway).

If your tank has an adequate process of nitrosofication working, but the nitrification process is not sufficient then you will see a reduction in the ammonia and a rise in nitrite.

The nitrosofying bacteria are quite rapid at getting going in a tank with sufficient oxygen in the water, and hence the first part of the 'cycle' will be a decrease in ammonia and a rise in nitrites. This can be quite rapid, and you may not even see the ammonia spike in some cases.

But the nitrifying bacteria take a lot longer to get established and defo need a solid substrate with a good oxygen supply to get established. These bacteria are also much more sensitive to changes in water chemistry than are the nitrosofying bacteria.
Hence, unless you've added a filter seeding agent, it could be 6 weeks before you have a well established process of oxidising nitrite to nitrate.

But even after 6 weeks, the tank is not fully 'cycled'. It has not fully matured and there are still processes that need to establish themselves.

Now, so far that has only looked at the single dogmatic pathway, but there are backward and side pathways that can go on. eg your tank can convert nitrate to ammonia in the tank via nitrite. Hence, you may a mature system but under certain anaerobic conditions the nitrate you produced from nitrification is converted back to nitrite and then eventually to ammonia. This will depend upon what bacteria are established in the tank (amongst other things).

So...yep, even if your tank is apparently fully cycled (noting that I doubt it is) you can get side and reverse reactions that could end up with a nitrite spike.

There are loads of other possibilities, and they depend upon the science of what is specifically in your tank (eg using different agents can alter the normal process seen in fish tanks).

ian

The problem is solved Ian but here was the scenario anyway...

180 litre tank set up 3 weeks ago..lots of plants and bogwood...6 SAEs and and the appropriate ammount of Tetra Safestart added with the fish....no problems watsoever...safestart did its job and after 10 days...Ammonia was zero...Nitrites were zero and Nitrates were 10....hence a "cycled" tank.....(My tapwater Nitrates are 5 BTW)

Anyway being a bit paranoid when it comes to water chemistry and especially with new tanks I continued to monitor the water parameters daily after the tank "CYCLED" for Ammonia and Nitrite and had no issues until the other day when something strange happened..Tested for Ammonia and Nitrite and both were zero...That was at about 9am...Next morning at 9am I tested again and this time ammonia was zero but nitrites were at 1.0....I immediately did a large water change (60% approx) and to be on the safe side added 100ml of Safestart....Next morning tested again and the problem was gone...Ammonia and Nitrite were zero again....

I guess Im just curious as to what happened...I did no filter maintenance etc etc...I mean is it possible that the Ammonia rose and fell so quick I missed it overnight and thats why I never seen it in the tests?

Moral of the story...Tetra Safestart does exactly what it says on the tin contrary to popular belief

Water Chemistry Paranoia is probably on the increase, and drugs companies need to see a big opportunity for making some extra money in the future.

I don't see anything wrong with tetra safestart either.....I've used it on test (as I was given a freebie) and found it did a great job.

There are some basic rules in chemistry (and they are also the rules of life).....

one set of rules (thermodynamics) say that something will spontaneously happen or not, and if it happens then another set rules (again thermodynamic rules) come in on which direction something will happen.

These rules will also set and predict the point of equilibrium in a system...ie the point at which things appear not to change.

This is all about being 'poised' to happen......but doesn't tell you 'when' it is going to happen.

So, we have a second set of rules (kinetics).....the speed at which something will happen.

Between those sets of rules, we have real systems.......but real systems are dynamic, and what you have at a particular point is exactly that: just because something seems to be at equilibrium (ie the process has gone to the end) doesn't mean it is static.

As we have more and more steps in a complete process (eg the conversion of ammonia to nitrite to nitrate) then we will see ups and downs at different stages depending on when we analyse that system.
Living systems have rate limiting steps in all multi-stage processes (it's a bit like traffic lights or someone dothering in a nissan micra holding back a mad-head in a Subaru )
The process of nitrosofication (ammonia to nitrite) is quite fast compared to nitrification (nitrite to nitrate)...you can only go as fast as the slowest step.

In a truly dynamic living system, then the key is all life on this planet is that life can balance the kinetics (speed of processes) to prevent a system going completely to equilibrium...ie life is able to seemingly fool the laws by rapidly controlling the speed of reactions at the nano-second level to keep life going (but we don't actually fool the laws; life simply works to delay the inevitable).

Death in a living system is when that living system is completely static......we call that stage 'static head'.

Your tank is a living system, and works under very complex scientific rules (in fact, so complex that we have to revert to a very philosophical level to explain it).

So if you measure a living system and it is static, then it is dead (and I can give you mathematical equations for that....but I won't as I need to do things others than sit a computer for the next few years).

Has that explained the possibility that nothing is actually wrong in your system....it may be simply the timing of taking readings.

ian