hmm, sounds like i have made a-lot bad assumptions here, so maybe I should start over from square 1,
The purpose of this application is for my arduino to detect the above compounds, for my new fishies and because I will never remember to test the water daily... was hoping for an automated solution, plus, ideal would be to have a response system if the air bubblers fail... I was told in this event I have an hour before o2 depletes and things start to die...
the other components only need to be checked on a daily basis
right now I have a test kit like a pool one:
https://i836.photobucket.com/albums/zz284/gdarbe/Tank Setup/tank0171.jpg
Was hoping for a solution that didn't require adding drops , then i could take readings all day... I also read about Galvanic probes, I wonder if those would work better for all day readings, but can it work for all to isolate and measure the different compounds, prolly not...?
I too like the idea of the CCD sensor ,, but a full array may be too much data for my arduino, which is why I had the idea of a single light sensor..... then a prism that i could rotate with a stepper motor to scan across the spectrum....
Also reading about other water tests based on conductivity which could help, but not sure if these tests can test what i need either.... but looking for any simple ideas that could work.
here is another water test I dont really understand but is very interesting: