That's a lot of math, Chem Geek!

We do have staining - but we had a brown pool over the course of several days - on 2 separate occasions.

5 was the highest reading we'd gotten. Right after we filled and it turned brown, it was only a 3. It couldn't have gone up 1.5 times when significant amounts of new water hadn't been introduced. So, I agree with you CG - it is suspicious. Not to mention the fact that the boy who did the test looked all of 12.

I no longer have the desire to know what the iron level is. I think I was just caught up in it because we fought it for several weeks. Truth is - it's not interfering with anything right now, so who cares. If water turns, I'll filter it out again. Done. Moving on.

Thanks for putting up with my neuroses!