Reply To: For new version

You have made your water body from a Plane (delete the default cube…add a plane.. in edit mode extrude on the Z-axis…something like that 😉 ), which is not wrong per se, but has the risk of getting the Normals flipped! This is exactly what happened in your file.:

In edit mode, select all and then press SHIFT+N to re-calculate the Normals. The reult will be a lot better out of the box and then you can still tweak some values or curves.