You simply MUST adjust your water pH when you grow indoors. the pH on bottled water can run as high as 10.5.

You will slowly poison the plants in an alkaline enviro like that. It needs to be 6.8 pH ideally.

The lower leaf death is normal if its a result of the shorter light cycle and poor lighting combined.

It appears on at least a couple of the pics that the leaves are old and have been dipping into the dirt from the watering. Another pic shows lower leaves dying but not the slowly fading yellow way you would want to see.

They look like nute issues. How often are you feeding them?