Help please, 8 plants already dead, one left :(. yellowing or n def. or sumthin

[LOC NAR on probation]

Your using tap water. Do you know the PPM's of the water. Maybe too high.

What kind and where did you get your rocks ?

To be on the safe side I would try what WeedHound says about soil trans plant. They are dieing anyway. Till you figure out what it is.