Dissolved Oxygen

September 30—What is meant by the term “dissolved oxygen?”  Explain how to conduct a dissolved oxygen test.  What level is required for most fish?  What is the dissolved oxygen level in your ecosystem?  What do you think the levels would be in a small pond?  A large river?


Dissolved Oxygen is the amount of oxygen that is dissolved or carried in a given medium.


Testing Procedure:
- Pour 250 ml of tank water in a testing vial.
- Remove ampule from box
- Place in vial and press down with enough force to break the tip, it will turn a shade of blue
- Swirl chemicals gently, wait for 2 minutes
- Compare to test examples

Water with less than 3 mg/l will not support any fish life
Above 5 mg/l is good

The dissolved oxygen level in my ecosystem is about an 8:

I think for a small pond, a 5 or 6 would be good.

For a large river I would expect maybe an 8 or 10.