Editing Category:Ammonia/Rough guide to toxic levels of free ammonia (section)

==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).<ref>US Environmental Protection Agency.  Ambient Water Quality Criteria for Ammonia, (EPA 440/5-85-001). January 1984-2004. [http://www.epa.gov/ost/pc/ambientwqc/ammonia1984.pdf 1984 PDF file], [http://www.epa.gov/waterscience/criteria/ammonia/99update.pdf 1999 update] [http://www.epa.gov/ost/standards/ammonia/99update.pdf 2004 update]</ref> <ref>Glodek, Garrett S. "Ammonia in the Closed System Aquarium," [http://www.fishchannel.com/fama_portal.aspx FAMA], June 1991.</ref>