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Re: Ammonia Testing Methods



     >Can one of the chemists on the list please comment on the difference 
     >between the two methods used to measure Ammonia in water - Salicylate 
     >vs Nessler? I am interested in obtaining either a LaMotte or Hach 
     >Ammonia Test Kit and would like to obtain the most accurate low range 
     >kit that I can, but don't know which method would produce the most 
     >accurate results. Is there any difference in quality (i.e. accuracy) 
     >between the LaMotte and Hach Ammonia Test Kits? All of my other test 
     >kits are variously either LaMotte or Hach and I have been very 
     >pleased with them and would like to stick with known quality if I 
     >can.
     
     The Nessler method works best in fresh water, but does not work in 
     salt water; it uses mercury salts, which can precipitate out of 
     solution in the presence of high chlorides.  The salicylate method is 
     preferred for saltwater testing, but is equally accurate in fresh 
     water.
     
     Generally, you only need to measure ammonia when cycling a new tank.  
     An inexpensive test kit will do, as you are really only interested in 
     the presence/absence of ammonia, instead of exact concentrations.  The 
     LaMotte kit seems a little pricey ($50, in one of my catalogs) for 
     short-term use.
     
     Regards,
     
     Mark