I often use a length of clear 3/8-in. tubing as a water level. One of the drawbacks of this simple, indispensable tool is the potential for leakage. If the plug dislodges, the colored water can run out in a hurry. I avoid the problem with a sturdy clothespinlike clamp from my local wine-making store. Sometimes called hemostats, these strong, plastic clamps securely crimp the tubing. No more leaks.
Felix Marti, Ridgway, CO