PaPond = based on your original post, I assumed that you wanted to monitor dissolved oxygen (which is a good idea).
Hach Chemical makes a multitude of water quality meters, and they also have simple test kits where you use chemicals, count drops, and watch for a color change. They actually are quite reliable tests. For example, I looked up their dissolved oxygen test kits, and you can do 100 tests from a $48 test kit. I tried to paste the web address for that test kit, but the string was lines and lines long. Perhaps go to their web site, address below, and search for "Dissolved Oxygen, Model OX-2P, 100 tests, Drop Count."
http://www.hach.com/ As for other water quality tests that you might want to consider, let's see if Bob Lusk spots this and answers that question. You certainly can test for nutrients (Hach makes a huge array of test kits, including kits for a number of common water quality measurements), but I'm wondering why? Are you concerned that nutrients are too low or too high?
Dave
