The difference between the odor and fatality is massive. You smell it LONG before it ever becomes dangerousThank you appreciate your answer. So i guess i can dump a bag of sulphur beads in the sump. Lot of people are afraid of hydrogen sulphide as it is toxic/flammable. I read somewhere that probioctic bacteria do reduce the toxic of HS. What is the worst thing can happen if somebody reactor creating the foul smell? I havent heard someone had incident regarding this HS for this hobby yet.