FishindRod, I misspoke a tad earlier. I just doublechecked my records and the water sample was actually drawn and sent off the day before the heavy rainfall. With that said, yes, the heavy runoff did produce the "tea color" and I never equated that with the tannic acid in the runoff. Thanks for the 'edumication" on that issue.

No fish kill, in fact, the RBT are still very active at the feeders.

I am going to re-test. I talked to the lab about that yesterday. I have some extra BPA-free, sterilized honey jars leftover from my honey extraction this year and I am going to use one of those for the repeat water sample.

I'm still a bit befuddled by this, particularly with no discernible swing in the pH.

Thanks again for your input.