Let the soil dry-out before doing anything else to her.

Tapwater ph is likely fine. Have you tried using it without running it through the Britta? No need to change things on this plant, but it would be worth a try on one still in the growth phase. Nothing worse than having to purchase and transport water or filters when it's almost free out of the tap. The bottled water ph is pretty low, and might be contributing to the claw effect on your lower leaves. Especially if the medium is losing it's buffering, (the buffers fade over time) or if soil ph was low to begin with.