I learned a valuable lesson today. While looking at my tank the last 2 days, I've noticed a lot of hair algae. I started thinking it was the ferts, since it just started coming in. I looked at my drop checker, which was blue. I thought that I was out of co2. Great. But wait... it still shows that it has plenty of pressure, but no bubbles in the bubble counter. Timer is on... working since I unplugged it and heard the solenoid. Hmmm.... Crank up the pressure, turn the needle valve up some, a few bubbles, then none. Ahhh, while messing around with everything on Friday evening, I moved my canister. Somehow, I sat it right on the co2 tubing. Crimped it shut. great... no co2 for 3 whole days. Ahhhh! Oh well. Learned that co2 tubing should be routed away from any heavy objects that may accidentally be sat on top of it!