coastal aquifer

Hey there,
Am in need of a help. I have a coastal aquifer that am modeling but am not getting the results most of the time it gives me the bottom (slice 2) hydraulic head different from the top (slice 1) I don't understand what to do.  I tried almost everything am new with the software.

If anyone is interested in helping me let me know.
Maybe there's some wrong that am not seeing help me!!!!!

FeFlow uses "head" to refer specifically to freshwater head. So, in case of saline waters  it increases with depth even in conditions without vertical flow (provided you have non-zero density ratio).

Equation linking freshwater and saltwater heads can be found at
http://www.feflow.info/html/help73/feflow/09_Parameters/Boundary_Conditions/Flow/hydraulic_head_bc_saltwaterhead.html

Thank you for the replay, its a helpful information

from the photo attached is my model and those values for the hydraulic heads equals the same as the top elevation of the model ( i dont know is it because my starting head =0 or something else is wrong with the boundary conditions)

also now i understand that those valuse are the freshwater but i looked for the Hydraulic Head BC (Saltwater Head) i could not find it....