Show level in cylinder

I changed the fill on your shape to have 4 stops then used this code to change the fill level when column D changes:

Option Explicit
Private Sub Worksheet_Change(ByVal Target As Range)

If Application.Intersect(Range("D:D"), Target) Is Nothing Then Exit Sub

Dim p As Double

p = 1 - Range("H4").Value
If p < 0 Then p = 0
If p > 1 Then p = 1

With ActiveSheet.Shapes("Can 1").Fill
    .GradientStops(3).Position = p
    .GradientStops(2).Position = p
End With

End Sub

See attached - add or change values in column D.

WBD