gully....i would think a call to these folks in Denton, Texas might be worth seeing if they could point you in the right direction. It appears their tests are geared towards city water and well water, but they may know of something that could help you. What do you have to lose but a phone call.

"This is a valuable option that you should consider if your water comes from a lake or pond or from a well in an agricultural region"

https://www.purewaterproducts.com/products/wt004

Fishing has never been about the fish....