Instead of buying marine salt from my local pet store, may I extract the salt directly from the bay? I am creating a brackish crabitat for my friends fiddlers (lets just say he forgot to do research).
not sure what bay you're talking about, but the only real problem i can think of with "grow your own" salt is that you don'y know what else is in the water.
ignoring any biological material and hydrocarbons, which should burn out when you bake the salt dry, there may be unusual metal salts, fertilizers, etc. from the local environment.
it ought to work, but really it sounds like a lot of work to me just to get sea salt
also keep in mind that salt does not precipitate solids equally. Different elements precipitate out at different salinities. Depending on how you collect it you may end up with a very unbalanced mix.
Yes I have a lagoon that "borrows" water from the san francisco bay. The lagoon itself is filled with kelp and other marine plants/algae. This along with some freshwater should do the trick! Thanks!