Sounds like an awesome venture thjakits, so right now you guys are making something like a prototype ?
Hach has test strips which measure Chlorine from 0 to 10 ppm
http://www.hach.com/free-total-chlorine ... allback=pf
They also have a hand held colorimeter that will test free chlorine and total chlorine..and from I understand chloramine can be determined by the difference of the two.
Culligan has a cheap kit too
https://www.filtersfast.com/P-Culligan- ... st-Kit.asp
If you want more accurate results it's best to get a UV-Vis spectrophotmeter, it's probably the cheapest chemistry lab instruments and you can get and it does a whole array of testing including free and total chlorine, it's one of the "workhorses" of our lab. They can be found used on Ebay for cheap.
Other chemicals of concern from water treatment plants are what's called "Disinfection Byproducts" here is a list from the EPA http://water.epa.gov/drink/contaminants ... oducts.cfm
These chemicals are more expensive to test for because they require instruments like Ion and Gas Chormatographs. you would probably want a chemistry lab to run those for you ...well at least until the facility in Panama has a lab.
Going back to DHHA; I haven't found any articles in regard to detrimental effects of it but I did find a paper on the degradation of Vitamin C which might be interesting.
http://courses.washington.edu/edtep586/Colleen%20.ppt
Unfortunately I could not open it up because the computer Im using doesn't have Office (I know weird)