I've had two plants one on each side of a 125 w/384w of PC lights, pressurized CO2 and modified EI dosing. For three years neither every threw a runner although they were almost 2' in each direction. I had an equipment malfunction and for about 3 months there was no CO2 injection and they exploded with runners everywhere. That was about a year ago. I removed the runners (the tank was literally overflowing with plants), corrected the CO2 issue and haven't seen another runner since.