We recently worked with an educational LaMotte kit that had a colormetric DO test. It gives a range for DO, but isn't precise. The whole kit is about $38 and has enough for a few tests. I'm sure you could order the packets for DO online though if you wanted to use this style of monitoring.
I haven't tried the stuff yet as I need to speak to the director of Grailville and/or the Little Miami Conservancy on the possibilities. I never really thought about using a kit for colormetric DO test. I will look into that. Thanks!
Reply to this comment...
Hi @belkinsa , Here's the page which gathers everything that has been posted on dissolved oxygen -- i hope this helps you find what you are looking for! You are welcome to comment and ask as many questions as you like :)