If i remember correctly, the Lemo/Lemo drop have bout half the airflow of the Petri, plus it creates a bit of drag in the way it flows through the rta. Your unit is probably fine, just make sure you have the airflow nut opened all the way up. Also as a side note, when this came out, it did have massive airflow, compared to other tanks available at the time. There were no sub ohm tanks yet, no goblins etc..