NH4 (ammonium) is a nontoxic salt, it is the ionised form of ammonia. It is useful to understand in the aquatic environment as although not toxic it self it does have the ability to instantly change to NH3 with a change in pH and or tempertaure.

To understand more about the link between NH3 and NH4 you can click here.

It is important to understand that is just the NH3 which is nasty and toxic to aquatic life and it is this that ideally needs monitoring.

The seneye device only measures toxic free ammonia NH3 and the seneye connect application allows you to look at free ammonia between 0.000ppm and 0.500ppm. The seneye.me website stores all the ammonia history from your device.

Ammonia test kits mostly measure TAN especially if they are marked as an NH3/NH4 test kit. The measurement is done by changing the pH of the water sample; you may have noticed how ammonia test kits normally have a small bottle marked harmful corrosive. Using NH4 temperature and pH to accurately work out how much NH3 is present is very very difficult click here to find out why.

Why does my ammonium NH4 go down when I do water changes click here?

If your ammonia is very high you may find it useful to learn how to control ammonia.