Sounds goo to me. Just make sure that you also eat some protein, calcium, and sugar. It's not good to have a diet consisting of seaweed for a long time.
I think that it is a good idea to shift your diet into more greens and green like vegetables. I am not too crazy over the idea of seaweeds though. I can only imagine the great benefits from them.
I believe that there are many vitamins in things like greens that are good for your blood cells and other bodily functions. I also believe that this kind of diet would be good for bowels.