Great info. I will keep it for backup.I would still recommend the TF-100 w/ magnetic speedstir. The bottle sizes are still a better value and should about all season. That kit is decent and equivalent to the K-2005, but has fewer tests for the season and does not include the FAS-DPD for accurate/elevated FC tests. You can hang on to it as a back up or for extra tests.
It’s definitely natural and solid/harder rock the deeper you go. In this part of Texas we’re lucky if we have more than 10-12” of topsoil before we hit limestone. Good for structural stability of homes, bad for anyone digging. I’m a heavy commercial general contractor and we hit limestone that is seems as hard as granite in this area.man. I am so happy for you that rock didnt go down deeper. Didnt lool natural. Probably burried it there when building.