Well, I haven't read up on this for a while so I very well could be mistaken about relative toxicities. However, suffice to say you want them both low!
As for NH4+, this is a good point. I"m pulling out my chemistry book...just a sec... Wow...I had to blow the dust off that one. According the henderson-hasselbalch equation which states that:
pH=pKa+log(NH3/NH4+)
we can calculate the relative amounts of NH3 and NH4 in solution depepending upon the pH. Ka of the reaction
NH3+ (H+) = NH4+ is Ka=5.6x10-10 so pKa is -log(Ka)=9.25. So lets assume a pH of 8.4 and we can solve to get that NH3/NH4=0.14. What does this mean?
This means that at pH 8.4 about 88% of the N's in this reaction will exist as NH4+ while the other 12% will be NH3 or ammonia. Thus in our aquariums, ammonia will always be much lower than ammonium.
This is why "ammonia" (meaning the sum total of ammonia and ammonium in our systems) is less toxic than nitrite more than likely...
Anway...just a minor point of interest...C
As for NH4+, this is a good point. I"m pulling out my chemistry book...just a sec... Wow...I had to blow the dust off that one. According the henderson-hasselbalch equation which states that:
pH=pKa+log(NH3/NH4+)
we can calculate the relative amounts of NH3 and NH4 in solution depepending upon the pH. Ka of the reaction
NH3+ (H+) = NH4+ is Ka=5.6x10-10 so pKa is -log(Ka)=9.25. So lets assume a pH of 8.4 and we can solve to get that NH3/NH4=0.14. What does this mean?
This means that at pH 8.4 about 88% of the N's in this reaction will exist as NH4+ while the other 12% will be NH3 or ammonia. Thus in our aquariums, ammonia will always be much lower than ammonium.
This is why "ammonia" (meaning the sum total of ammonia and ammonium in our systems) is less toxic than nitrite more than likely...
Anway...just a minor point of interest...C
