Go to the Article: The Ultimate Guide to Dungeness Crab
"it should literally be as salty as the sea: 35 grams of water per liter."
I hate to tell you this, but adding 35 grams of water to a liter of water will not make it any saltier.
(Feel free to delete this after the text is fixed)
Interesting that you use water to boil shells in to make stock, best use for shells, like lobster shell is to break them up and using a pressure cooker to turn them into crab butter by adding a 500gm of unsalted butter and cooking for about 30 min. Shells are not water soluble but they are oil/butter soluble. renders out all the beta carotene and IMHO the flavour.