Learned something new today.... I think.
I run a still to make my own water. I can do a gallon every 5 hours, which is not ideal, but it does a good job of keeping up for most of veg and about half of flower. After the first few gallons, there was a pretty impressive crust of calcium at the bottom of the pot. So to get cute, I put in some citric acid with the tap water to "proactively" chelate the minerals before they cake on the tank. This works. BUT, I have a feeling some of the citric is carrying over (the inside of the is showing a good amount of dried citric acid all the way to the top of the still). In testing my distilled water with the chemical kit, the pH is ~5.5. I could be wrong, but that seems a bit high for the small amount of CO2 that dissolves into it.
Gonna have to clean it out and see if I can get the ~6.5 I was expecting.