With our pool, the bubblers are turned on/off by manually opening/closing a valve at the equipment pad, so it's possible the valve to those is closed. We can control the height of the bubblers by only opening the valve partially. If those are lighted bubblers, there must be a control for them somewhere (but since ours aren't lit, I can't offer advice on those types of bubblers). Do you have a valve at the equipment pad labeled "Bubblers" or "Water Feature"?