Dear Bizi
If you decide to take an additional B complex besides the amounts that are arleady in you multivits, and which already exceed 100% of the RDA, i think you should seek out a BALANCED b-complex. that B-50 is not balanced - as in the quantities of the different vitamins are not in proportion to each other, as i explained before. I suppose if you just want to finish up what you have so as not to throw money away, once a week will be ok as MrsD suggests.
When you get the testing done, I would also talk to your doctor about any real need for additional supplementation, but let her know about your multivit (bring it) and ask if it is sufficient. Bet s/he will say yes. If s/he suggests additional supplementation, ask how much of what. Based on that, seek something with balanced proportions and reasonable dosages.
I agree wholeheartedly with MrsD's assessment of info obtained from "health-food" stores. They are not scientifically sound sources of information. Some of the salespeople are naive and misinformed, but they genuinely believe what they tell you; others don't know diddly but will say whatever sounds good to move product... either way not much different than the pharmaceutical company/reps, except there are fewer regulatory constraints on these products.
I am glad you are dropping the Chlorella... the "super-food" aspect was more about its potential as a concentrated protein source, at a time in history when people weren't getting enough. Now we are getting plenty of protein, even in excess. So, even if the stuff weren't toxic, i don't see that it would be useful.
I wish i could say, "I drink to your health," but my stomach won't let me do that... LOL

love
~ waves ~