Arduino Controlled Aquarium

Using Arduino Project Guidance
1

Hello,

My big Arduino project is going to be an Arduino controlled aquarium.
The system will have a lot of functions.

Thing is, I'm having a problem with measuring ammonia and oxygen in the water.
I need to measure the ammonia and oxygen so the Arduino can understand.
I'm not going to buy hundreds of dollar cost sensors found on eBay.

I need a cheap creative idea for measuring ammonia and oxygen.
For ammonia I have two basic ideas.

  1. Use color sensor with this:http://www.amazon.com/Seachem-10-Ammonia-Alert/dp/B000255R5G
    That way I can tell the approximate ammonia level.

  2. Using the manual measure kit, just making it automatic (not easy) and using color sensor for the reading.

As far as oxygen measure I'm out of ideas for now.

Looking for more helpful and creative ideas.
Thanks.

2

For ammonia I have two basic ideas.

  1. Use color sensor with this:http://www.amazon.com/Seachem-10-Ammonia-Alert/dp/B000255R5G
    That way I can tell the approximate ammonia level.

  2. Using the manual measure kit, just making it automatic (not easy) and using color sensor for the reading.

Have you determined that an affordable color sensor will do what you want?

If you determine that the amonia or oxygen levels are too low or too high, what do you plan to do about it? It seems pointless to measure something you can't control. Like a lot of programming metrics.