Lugol's Solution Question

[Seafan]

Wondering if there is a difference in the lugol's solution you buy in a pharmacy versus stuff at the lfs? Is it safe to do a coral dip in the pharmacy type, and if so how much lugol's to water do you use? Also read some people use the pharmacy version to supplement their tank for iodine, is this safe or would it wipe out all the beneficial bacteria because of the iodide in it as well? Or for dosing tank do you strickly use lfs iodine? If you supplement tank as well with lugol's how much do you add per gallon? Sorry if this is winded or confusing, I am just confused right now, been a long day and have a brain that is in dire need to be dipped. Thanks in advance.