When the loaf comes out of the oven, see how crunchy the crust is and how light the loaf is inside.
Remarks
This recipe only works well with ocean water (Atlantic, Pacific, Indian); the water from the Mediterranean is too salty, so needs to be diluted with a little fresh water.
In spite of the name, there's no "sea" flavour to this bread. Delicious as it is, you'll not find any trace of the slight iodine taste of the sea (no doubt this disappears during cooking). To get this flavour, you would need to add seaweed extract or other seafood.