Hello, my sodastream jet was not carbonating drinks as well as it used to, the drinks came out very flat, barely bubbly at all. After having tried a new gas cylinder and still having dissapointment, I dismantled it and got acsess to the valaves that determine when to release the pressure, and tightened it by rotating it 90 degrees. There are videos on this on youtube. Unfortunately, i broke the second valve in trying to do this, however, despite that breakage, the machine now carbonates better, despite leaking gas through the broken valve. The plastic parts inside are fragile. If you do this yourself, i would warn not to tighten the valve too much, as that may increase the pressure too much. I would do it in 90 degree increments until you get the right bubbles.