Ahhhh The famous Fina cough ,, quite honestly I have seen it debated by some great minds ... and no one has come up with a good reason ,, it is a hit or miss thing ... I have ran Fina 4 complete cycles ,, and only ever coughed twice .. but one was a bad ordeal .. almost passed out .. it is a bitch .. but I can honestly say I have no frigging clue what causes it .. so I am not sure if that means you made it right or there is something about the chemicals in the kits that would make you cough even without the pellets >>?????