I am also taking roughly 400 mg magnesium twice a day so if chlorella can't do it then I'll know its the mag. As for abx I'm on 500 mg Biaxin daily and 2 g Rocephin. And 400 mg of artemisinin.
Thanks for any info.
Some people do not digest it properly and therefore do not get the desired effect. The enzyme cellulase helps (in digestive enzymes at healthfood store).
Be sure to take Chlorella 30 minutes before meals. (Do not take it at the same time as Vitamin C. ) This way chlorella is exactly in that portion of the small intestine where the bile squirts into the gut at the beginning of the meal, carrying with it toxic metals and other toxic waste. They are bound by the chlorella cell wall and carried out via the digestive tract.
My guess is - 800 mg of Mag is a lot and I was always told to then cut back until normal BM.
Take care.
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There is lots written about the need for a steady supply of mag rather then one or two larger doses a day.
Too large a dose of mag will clean you out for sure.
Well, I'd say you got some clear cut anwers from which to choose 
As you can see, everyone reacts a bit differently to meds & supplements.
Are you taking any probiotics to help counteract the antibiotics? If so, are they the good type with Acidophilus and Bifidus and kept the in refrigerated section of the health food store?
My LLMD told me to increase my dose of probiotics if I got intestinal problems and to take the increased dose until the problems went away.
Hope some of these suggestions help.
Also, some people are allergic to it. My sister breaks out in a total body rash that her MD thinks could be from the Chlorella.
And yes, magnesium can also do this in high doses.
I know that I am safe if my own doctor takes it or gives it to his child. This is the case with Biopure. He carefully monitors the quality because literally all patients end up taking chlorella, and if patients end up with unusual reactions, he is certain to hear about it.
Do not forget that one can be allergic to any substance for one reason or another. A friend of mine is allergic to a certain brand of health food store salt!
Some people have problems digesting the cell membrane of chlorella. Cellulase, an enzyme available in health food stores, resolves this problem.
If you take Vitamin C, take it as far away from Chlorella as possible, after meals.
The chlorella should be taken 30 minutes before the meal.
If you have side effects: Most side effects reflect the toxic effect of the mobilized metals which are shuttled through the organism. This is instantly avoided by significantly increasing the chlorella dosage, not by reducing it, which would worsen the problem because --- small chlorella doses mobilize more metals than are bound in the gut; large chlorella doses bind more toxins than are mobilized.
Taking chlorella together with food also helps for some people, even though it is less effective that way. If you have a problem with Chlorella pyrenoidosa, try Chlorella vulgaris - it has a thinner cell wall and is better tolerated by people with digestive problems.
Whatever - make very sure that the chlorella you take is "clean". After all, you are trying to get rid of the toxins and not accumulating more.
Take care.