The algae of which you speak is similar to spirulina, (if it's not the same thing - I always thought they were the same thing for some reason) and is perfectly safe - a protein supplement. Some people get energy highs off of it. I have no idea why - it's never happened to me personally - but trust me, it's safe, I'm pregnant and I was taking it for awhile (only reason I stopped is that I haven't bought any more).
As far as gingko - that's mainly more for mental alertness and increasing blood flow to the brain - useful for intellectual pursuits, but if you want more energy as such it may not work as well. I take that too, at least partially because my long-term memory isn't so great.
OK, now that I'm done a string of naturopathic ramblings, I toddle. Hope this helps.