I've heard anecdotally that seaweed can be a good fertilizer, but the anecdotes never specify which kind of seaweed is good. I tried some bladder kelp with indifferent results. Salt water though? That doesn't sound right. I think the fertilization properties of salt are pretty much summed up by its role in the phrase, "Burn it down and salt the earth."
I’ve looked at a lot of different solutions, and in my humble opinion Aspose is the way to go. Here’s the link: http://aspose.com