Here is what I said:
This is why it is an urban aquarium myth that any time one sees .25 or .50 ppm of ammonia a big water change must be done immediately. It is not the Total Ammonia which matters, it is ammonia as NH3 (the toxic gas) that is important, especially in the shorter time periods we have in cycling. In water a lot of the chemistry changes for a lot of things.
Here is what it means
- So here it is. An API test kit reads Total Ammonia. (As do many hobby ammonia test kits.)
- Total ammonia is the suml of both ammonia NH3 plus ammonium NH4+.
-Ammonia NH3 is highly toxic to almost all life forms. According to the Merck Veterinary Manual, for fish NH3 becomes an issue when it hits 0.05 ppm. So this is the key level we need to know when all we have is a Total Ammonia reading.
- The problem is only a test method which specifically reads just NH3 ammonia will tell us how much NH3 is in the water.
- No matter what amount of ammonia NH3 or Ammonium NH4+ is initially dissolved in water, based on the pH and temp of that water, one ends up with both forms no matter which one of them is introduced. The converse of this is one can reduce Total Ammonia effectively to 0 by removing only NH4 or NH3. As one is removed the balance gets restored almost instantly so there is more of what was removed that can again be removed. Eventually this will result in a 0 Total Ammonia reading.
What this means is that if one doesn't use an ammonia calculator to determine how much NH3 is in any Total Ammonia reading one has no clue how much NH3 there is. In one tank 2 ppm of Total Ammonia may be pretty safe over the short term while .25 ppm may be toxic in another tank. Just using an API (or similar) test kit will not tell us how toxic any Total Ammonia reading is.
But don't accept what I say. Here is what the Merck Veterinary Manual has to say on this topic. I did not write it but I did add the
Italics to some of the text
NH3 is highly toxic and frequently limits fish production in intensive systems. It is also dynamic, and when it enters the aquatic system, an equilibrium is established between NH3 and ammonium (NH4+). Of the two, NH3 is far more toxic to fish, and its formation is favored by high pH (>7) and water temperature. When pH exceeds ~8.5, any NH3 present can be dangerous. In general, a normally functioning aquatic system should contain no measurable NH3 because as soon as it enters the system, it should be removed by aerobic bacteria in the environment.
Ammonia test kits do not typically measure NH3 directly but instead measure the combination of NH3 and NH4+, referred to as total ammonia nitrogen (TAN). A TAN <1 mg/L is usually not cause for concern unless the pH is >8.5. However, if the amount of NH3 is increased, an explanation should be sought. The amount of toxic NH3 present can be calculated using the TAN, pH, and water temperature.
When NH3 levels exceed 0.05 mg/L, damage to gills becomes apparent; levels of 2 mg/L are lethal for many fish. Fish exposed to ammonia may be lethargic and have poor appetites. Acute toxicity may be suggested by neurologic signs such as spinning, disorientation, and convulsions.
You can find the full information from the Merck Manual on the nitrogen complex and fish here
Nitrogenous Compounds
So here it is in plain English:
If all you have is a Total Ammonia reading and no other information, you have no idea if that Total Ammonia level is harmful, fatal or neither. So no idea if water should be changed or not.
I have been using this ammonia calculator for about 10 years. Here are step by step instructions for how to use it. If you are still not sure, shoot me a PM and I will be glad to help.
http://www.hamzasreef.com/Contents/Calculators/FreeAmmonia.php
1. Choose NH (NH3 + NH4)*
2. Enter in the total ammonia reading from your test, choose ppm.
3. For a fresh water tank, enter 0 for the salinity.
4. Enter your tank’s current pH.
5. Enter your tank's temperature and choose F or C, whichever applies.
6. Click Calculate.
The number you want to know is the one for
NH3.
[* If your kit measures ammonia as nitrogen aka –N, choose NH-N (NH3-N + NH4-N) in step 1. above. Most hobby kits do not read as nitrogen, -N.]
SeaChem may be stumped by your readings, I am not. The odds are that they are not real. No matter what sort of supposed bacterial supplement one adds to a tank, what will be there when the tank is cycled is the pretty much the same in every tank. So for the sake of argument let's apply this to Stability. Even if it is worthless, a tank will still become cycled with the proper bacteria over a number of weeks. This means your tank should have cycled a while ago to accommodate your small fish load. If your tank is indeed cycled, then the only explanation is that your ammonia reading is not real. This problem is not as uncommon as many might think. For example, iron in water can throw off test results for ammonia.
Again don't believe me about false positives. Do a Google search for "ammonia test false positive" and/or "api ammonia test false positive"
I have surfed all sorts of sites such as the Hach site. They make lab grade testing equipment. We pay $6- $8 bucks for an API ammonia test kit that performs 130 tests (between 16.25 and17 cents/test). Here is what an actual really accurate lab grade meter can run:
HQ440D Laboratory Ammonia (NH₃) Ion Meter Package with ISENH3181 Ion Selective Electrode
Product #: 8507600
USD Price: $2,791.00
Here is their cheap kit, only $94.50 plus shipping
https://www.hach.com/nitrogen-ammonia-test-kit-model-ni-8/product?id=7640220993&callback=qs and then there is this:
Ammonia Reagent 2 Powder Pillows, pk/100 $37.00, or 37 cents every time one tests. The first 100 tests are part of the initial purchase price. After that the $.37 charge applies to every test.
Both a far cry from $8. But it should help one understand why our hobby kits may be helpful but also why we must be careful about how we accept/interpret the results.