Please observe caution when maintianing your planted tanks, it can be a quite dangerous hobby. Actually the only danger i was in was caused by my own carelessness. It was quite a disturbing experience that made me take a little break from the hobby for several months. But anyway, the warning to be heeded. My 5lb. CO2 tank had finally run dry, so i throw it into the cab of my truck, I had helped my buddy move so i took out the cradle i built for the tank. I usually attached it in the bed of the truck with a bungee cord. I dropped it off, and being Southern Illinois, i could pick it up in a few hours. So i went home and of course forgot about bungee cording the tank cradle in the bed of the truck. After pickup i decided i didnt want the tank rolling around in the bed possibly causing the valve to rupture. So i put it in the floor board. I was about a minute from home when i heard the hiss start. THE SAFTEY VALVE HAD RUPTURED!!! with no apparent cause. In the course of 2 seconds i couldnt see a thing, white out in the cab. I took a big breath as soon as it started but i could taste the sour CO2 in the air. I rolled down the window but it made no difference, i still couldnt see at all. I got over to what i thought was the side of the road and by that time had to have air. I jumped from the truck just as my vision started to go spotty. I couldnt tell if there were any cars coming i just had to get out. After a couple good breaths i was fine and drove back home. The people who saw all this had to assume i was manufacturing meth in the truck. There was a big chunck of dry ice in the tank for a coulple hours after i put it on the patio. This situation could have been worse, if i had been in my fiance's car, the tank would have been in the trunk, where i may not have heard it, only passed out on the road when it flooded the passenger compartment throught the back seat. Or worse if i had taken her up on the offer for her to drive and go get it, she wouldnt have known anything about what was going on and lord knows what could have happened. Please learn from my foolish mistakes, it may not be very common for something like this to happen but im proof that it does.