I´m sorry I´m late in but it took some time to type this. It can be seen as I repeat what other have said - but because I put time to try to explain my point of view - i press the send button
What´s happen is that you have stalled the nitrification cycle just before the second phase. A complete nitrification cycle is a two step reaction that will be seamless when you once have established both steps. First step is that rather many different microorganism convert NH
3/NH
4 into NO
2 It mostly autotrophic bacteria lika nitrosomonas but also another type of microorganisms - the archaea´s is know to have these abilities. This step will normally be established during a few days.
The second step is the conversion of NO
2 into NO
3. This conversions is done by truly autotrophic bacteria - mainly from the nitrobacter and nitrospira genus. In certain circumstances it is known that the process can stall here - NH
3/NH
4 is steady converted into NO
2 but the conversion of NO
2 into NO
3 is slow or none. In freshwater - NO
2 is deadly for fish but in saltwater it is not taken up into the fish and therefore not as toxic.
IMO - this situation with a stalled nitrification cycle just before the second step happens when a total clean aquarium is started with adding higher amount of NH
3/NH
4 - a fishless cycle and there is not enough of inorganic P for the growth of the second stage bacteria. There is studies that indicate that high NH
3/NH
4 concentration by itself can slow down the actions of the second step.
With a stalled nitrification cycle I mean that NH3/NH4 will be steady processed into NO2 but a low amount (or non) of NO2 will be converted into NO3. I put in bold here because I know that the thread will be filled up of statements that a stalled nitrification cycle is a hoax. The first step will not stall - ammonia will still be processed but the second step can stall and nitrite will be build up.
Because I normally start with a fish where I manage the NH
3/NH
4 excretion with help of my feeding regime (
see here) I have never (since I start with that method) experienced any stalling at the second step.
But in the old days I have experienced it and I normally just keep on adding nitrification bacteria and wait. Some people have experienced a quick start of the second step when they get some inorganic P (PO
4 - phosphate) in the water if it had stall. My experiences is also that you can never use dilution as a problem solver with nitrite. I normally do not do any WC.
Some people say that you can add fish in spite of the nitrite level in saltwater - and yes you can in most cases but personally - I do not add fish or other animals if I read high NO
2 levels. Now when you are in this situation - just wait but you can speed it up a little with help of adding nitrification bacteria (on a daily basis) and a very, very small amount of frozen food - just a very, very small pinch in order to get in some phosphate for the autotrophic nitrification bacterias growth. When it kick in - it goes fast. I once read around 3 ppm NO
2 in the morning and in the evening it was gone.
To the measurements. In my experiences - most total ammonia tests often show 0.25 ppm even if the total ammonia is 0. Total ammonia include NH
3 and NH
4 and the ratio between them is depended of the pH. It is important - because it is the gas - ammoniac - NH
3 that is toxic - the ion - ammonium - NH
4 is non toxic. In pH of 8 and 25 degree C - around 5% is in the toxic form NH3. If your API test read 0.25 -> only 0.0125 ppm is in the toxic for. Att pH 8.5 it is 15 % and around 0,0375 ppm of the toxic form. Non of these concentrations is acute toxic. so even if it is a real reading - 0.25 ppm total ammonia (as in many tests) is of no concern
As other have pointed out - to try to analyze NO
3 if NO
2 is present is meaningless - you will have a huge false reading. All NO
3 test I know of is based on three steps - first - convert all NO
3 into NO
2 - second - read NO
2 - third convert the colour after a certain time into NO
3 again (The chart do that) If nitrite (NO2) is present in the samples - you get a wrong reading. Often it is between 50 to 100 times higher than the real NO
3 value.
Do not add any more NH
3/NH
4 - that step is already working - you need it to work once - after that it is established and will work for most time. However - add more nitrite oxidizing bacteria like nitrospira and make it possible for them to grow. A very good idea in the start is to use a foam filter like the one populare in freshwater for the first weeks
Sincerely Lasse
