Got this from some research posted on the net. "If your sea salt is gathered from the same region as the fish, then I wouldn't think you'd have any problem. Just be sure to dilute it to a salinity (Specific gravity) of 1.020 to 1.022. If you can get a sea water sample from your region and check it with a hydrometer, it may be a different salinity, so use whetever you have locally as your base salinity target and you should be fine. Gourmet Sea Salt or Bay Salt (used for seasoning food) could theoretically be used since it is usually produced by the evaporation of salts from the ocean or a bay. It is however, much more expensive to use than my own preference (Instant Ocean brand of aquarium sea salts). The biggest differences between the two are that Instant Ocean has a smaller grain size and therefore dissolves quicker and more easily and it also is cleaned of impurities that may be present in Sea Salt or Bay Salt. Commercial aquarium sea salts also have been analyzed and upgraded to include specific minerals and salts that are necessary for the good health of your fish. Food-based sea salts may be lacking in some of the essential chemicals needed for their good health. It's exactly those impurities within sea salt and bay salt that provide the flavor desired in the foods that are seasoned with it, but those impurities may or may not be beneficial to aquarium fish. For instance, one of my favorites, black sea salt from Hawaii, contains a certain amount of black lava as a flavoring agent...This is fairly inert and won't hurt your fish, but it won't help either. Black lava specks in your white gravel might not be so appealing from an aesthetic point of view. Pink Alae sea salt from Hawaii, on the other hand contains a large amount of red clay which would NOT be beneficial to aquarium fish as it could scratch their sensitive gill surfaces while suspended in the water column. In essence, if you could find a relatively pure source of gourmet sea salt with almost no impurities, you would do "OK" by your fish to use it, but my advice would be that it is better to be certain of the contents (as you would be with commercial aquarium sea salts), for the better health of your fish." Since I'm from Philippines I have access to unrefined sea. I purchased the salt where i got the fish. It worked for me. If I get sea water it will weigh around 900lbs. If I use sea salt I will need 20 lbs of it. Sea salt cost $2 per 20 lbs. Unlike synthetic ones which cost $50 (good for 75 gallons). Then i purchased test kits around $20 and supplements around $10 which are good for 200 gallons. My tank is 1 year old now. I got Tomato and Percula Clown fishes , Black and Clown Trigger fishes, Yellow Tangs, an unidentified eel and some invertebrates.