The same reaction occurs when someone takes a few chlorella pills. Is the chlorella infested with pathogens or is there something else going on?
Chlorella contains a lot of chlorofyl, the stuff that makes it green. This stuff is very healthy for your body. It triggers a lot of mechanisms in the body to fuel or to get rid of things.
Lettuce, when grown perfectly, contains also a lot of chlorofyl. If your bodies aren't used to it, it starts to work some things in your body.
What happens is your body wants to replace toxins in your body with the good, the healthy stuff. The body wants to get rid of the things it doesn't want to be there any longer. Some toxins can only leave the body with certain carriers to bind to, like heavy metals. Chlorella is used for this, to bind heavy metals to it, so it can be transported out of the body. This mechanism that is used is diarrhea. As long as you keep feeding it as much chlorofyl as needed to get rid of any toxins, you keep getting diarrhea. And that's OK. As long as you keep yourself hydrated that is.
I had series of chlorella and just for a few days, my stomach and bowels where upset. Not that heavy or realy unpleasant, but out of track a bit. After that, my body gained a lot more energy, a lot more rush and excitement. A good feeling and something that made the diarrhea forgotten in no time.
Your stomach, your bowelsystem, your lymphsystem, all these elements will get a detox by getting enough chlorofyl. So no worry, it's natural.