Is blue-green algae the same thing as spirulina?

Is blue-green algae (Chlorella) and Spirulina the same thing? If not can you take both at the same time?
No, they aren’t the same plant, but they are very similar plants. Both are algae that are nutrient rich (vitamins, minerals, protein, amino acids, chlorophyll, etc), but they are different species. The different between the two is much  like the difference between a yam and a potato

You could take blue green algae and spirulina together, but you shouldn’t take the maximum dose of either. Taking both may result in more fiber and chlorophyll than your body is ready to handle.  In other words, if you take the recommended dose of both at once, you might get the runs. Take about 1/2 the dose of each (or lower if you don’t take either yet), and you should be good. You can always slowly increase your dose later if you’d like to.

Blue-green algae and spirulina are both algae that are very rich in chlorophyll and many other nutrients.  Both are often referred to as green super foods.  Apparently one comes from blue or green algae and the other one comes from blue/green algae. Barley grass, wheat grass and alfalfa are some other green super foods. Blue-green algae is supposed to be very good for cleansing and detoxing your colon; and spirulina is supposed to be a very good energy booster.