Hello to all,
I have a project about measuring the ammonia (NH3) in water. Now, I'm looking a sensor, which can measure the ammonia. I searched a lot but I only see this sensor "404 | ysi.com". The price of one is about 250$, it is too expensive for me. So, any members of this forum had tried to use or know this sensor before?
Can you show me the cheper sensor?
What concentration of ammonia in water are you trying to measure ?
The concentration of ammonia in floor cleaner is usually detemined by measuring the density, which is a fairly simple procedure also used in beer making. The relationship between apparent density and ammonia concentration is easily determined, as long as you can assume there isn't anything else in the liquid.
Measuring the low concentration of ammonia in polluted stream water would be another issue entirely, quite difficult and probably not possible with a "sensor".
You might also want to look at how they measure dissolved ammonia and related substances in aquarium water.
The ammonia gas sensor you looked at will meaure ammonia in air, and it is less sensitive than your nose is.
I know this sensor, but it is gas sensor, not aqua sensor. I need a sensor which measure the total amoni ( NH3 and NH4+) in water.
If you know any informations, please give me. Thanks you very much! 
michinyon:
What concentration of ammonia in water are you trying to measure ?The concentration of ammonia in floor cleaner is usually detemined by measuring the density, which is a fairly simple procedure also used in beer making. The relationship between apparent density and ammonia concentration is easily determined, as long as you can assume there isn't anything else in the liquid.
Measuring the low concentration of ammonia in polluted stream water would be another issue entirely, quite difficult and probably not possible with a "sensor".
You might also want to look at how they measure dissolved ammonia and related substances in aquarium water.
The ammonia gas sensor you looked at will meaure ammonia in air, and it is less sensitive than your nose is.
Yes, That is my ideas, I want to determind the total concentration of ammonia in aquarium water. It consists of NH3 and NH4+.
As I know, to determind the concentration of NH3, we have to measure the pH and total concentration of ammonia. I measured the pH and now, I need a sensor to measure the total concentration of ammonia. If you know any sensor with cheper price, please give me. Sorry about my bad english. Thanks you very much.