Free Ammonia vs. Total Ammonia, please help

[bleeding]

Can anyone explain to me the difference between free ammonia (NH3) and total ammonia (NH4+)?

I think i read that free ammonia is more deadly, and total ammonia, or ammonium, is relatively harmless?

In recent posts, i have been trying to solve a horrible water problem with ext. high ammonia levels. Just got a new eheim 2028 running on the tank, and the ammonia test kit (which is a seachem kit with the little yellow sensors) is reading that i still have high total ammonia levels, but only trace amounts of the free ammonia. By trace i mean .01 ppm.

 

[NeonJulie]

Yeah, I have that sensor as well. It goes off pretty high whenever I use Prime/adding new water. I believe Prime turns the chlorines into that form of ammonium (the safer kind.) If you read the back of the bottle, it says something like that.

 

[Star_Rider]

prime adds the extra hydrogen ion to NH3(ammonia) converting it to NH4 (ammonium). it does this when it breaks the clorine ammonia bond in chloramine.
NH4 is 'Less' harmful to the fish and is still available for the bacteria in the nitrogen cycle(stage 1 i like to call it...LOL)
as opposed to 'ammonia removers' which locks the ammonia(read as this lock can break and ammonia can be released.
these ammo locks are useful when transporting fish and can lessen the harmful affects of ammonia.(many fish shipers add an 'ammo'loc' to the bag just prior to shipping, they also don't feed the fish for 2-3 days to reduce waste).

free ammonia is NH3 (uniodized ammonia) which is highly toxic to fish

total ammonia NH3 plus NH4+

I believe that ammonia(NH3) will exist at very low levels in the aquarium(since the bacteria do not immediately consume it) although we strive for 0 ammonia in reality the free ammonia should be maintained to a maximum of .02 mg/L.(IMHO)
to use total ammonia to try and determine free ammonia you need a table that shows temp/pH and total ammonia ppm (will show max total ammonia for the temp and pH)
to lower total ammonia you do it thru water changes.
this is probably a better way to determine water changes than using nitrates as the indicator.(IMHO)

 

[Hereford]

Star Rider is spot-on about ammonia toxicity as a function of pH and temperature. The Red Sea test kit includes a chart that maps this relationship. As a example: If there is 1.0 ppm total ammonia measured at a temperature at 79 deg. F with pH at 8.4, the toxic component is 14% or 0.140 ppm. Higher temperature and higher pH both contibute to increased toxicity.