Log-in or register your account to remove these ads! Its free and an e-mail isn't required.
TAN
From The Aquarium Wiki
Contents |
[edit] What does it mean?
TAN stands for Total Ammonia Nitrogen or just Total Ammonia (TA).
It is a term used to correctly identify the type of ammonia being measured in many so called Ammonia test kits.
Most test kits on sale often actually test free Ammonia (NH3) which is very toxic and Ammonium (NH+4) which is non-toxic and lump them together.
The ratio of Ammonia to Ammonium can varies depending on many things, but usually the two main characteristics of water, pH and the temperature of the water in Centigrade is measured and the ratio is calculated from this. This is often accurate enough for the average aquarist.
- See Ammonia for more details.
| Temp C/F | pH 6.5 | pH 7.0 | pH 7.5 | pH 7.7 | pH 8.0 | pH 8.5 |
| 20C (68F) | 0.125 | 0.395 | 1.239 | 1.95 | 3.81 | 11.15 |
|---|---|---|---|---|---|---|
| 25C (77F) | 0.179 | 0.565 | 1.766 | 2.77 | 5.380 | 15.242 |
| 28C (82F) | 0.221 | 0.696 | 2.170 | 3.396 | 6.55 | 18.156 |
| 30C (86F) | 0.253 | 0.798 | 2.482 | 3.78 | 7.450 | 20.292 |
| Generally, any value above 0.5ppm is dangerous | ||||||
Therefore a theoretical ammonia reading of 2ppm in a test kit for water at typical values of 25°C (77°F) at a pH of 7.5 actually contains 1.77% ammonia and 98.23% of ammonium.
That works out from the chart above at a level of 0.035ppm of pure ammonia which at first glance seems very low. But the hobby has traditionally based its danger readings on the value of total ammonia and not pure ammonia. So this level is classed as tolerable but likely to be harmful over the long term.
[edit] Rough guide to toxic levels of free ammonia
- (ppm)
- 0.020 to 0.049 is considered 'tolerated' but will cause long term harm to its growth, immune system, health, etc. especially to eggs or very young animals.
- 0.050 to 0.199 is perhaps tolerated for only a few days and is very harmful.
- 0.200 to 0.499 is perhaps tolerated for a day or two and will probably kill.
- 0.500+ is deadly and will probably kill within a day.
(Individual species of fish, amphibians, invertebrates etc. vary enormously on their tolerances of low levels of ammonia and the issue is made further complicated as young are far more susceptible to ammonia than older animals).[1] [2]
[edit] References
- ↑ US Environmental Protection Agency. Ambient Water Quality Criteria for Ammonia, (EPA 440/5-85-001). January 1984-2004. 1984 PDF file, 1999 update 2004 update
- ↑ Glodek, Garrett S. "Ammonia in the Closed System Aquarium," FAMA, June 1991.
[edit] Links
- Ammonia in aquariums and safe levels by the OATA
- Free Ammonia-Nitrogen Calculator & Information
- How to calculate the level of free ammonia at certain pH and temperature in water by Professor James E. Alleman (Archived link March 2005)
- Koi and Water Garden Society - Free Ammonia calculator
- Ammonia Toxicity to fish Tables
