Question: What are good resources for teaching middle school age children about water quality parameters?

You might like some of the work that North Brooklyn Boat Club has been doing in their Ed Shed. They also have a nice workbook designed for kids that might be a good model for developing other kinds of site-specific curriculum.

I think a fun way is using these Leaf Pack kits.

I ended up going with the LaMotte/Earth Force low cost Water Monitoring kit (Code 3-5886). I was able to find it for about $38 on Amazon. The kit says it has all the materials to monitor coliform bacteria, dissolved oxygen, BOD, nitrate, pH, phosphate, temperature, and turbidity

https://publiclab.org/notes/stevie/04-18-2018/lamotte-and-earth-force-low-cost-water-monitoring-kit?_=1524065006

@pdhixenbaugh wrote this up for working with a group of teenagers on #coqui kits -- https://publiclab.org/notes/pdhixenbaugh/08-22-2018/diy-science-lesson-with-the-coqui