IMO, pearling immediately after a H2O change is caused by nothing more than the fact that the water you are introducing is saturated with O2. Once you exceed the sturation point, all the O2 being produced by the plants is not absorbed into the water and they pearl. It's not "bubbling out" of the water.
this might be true if you are taking water directly from the tap....
how about water that has been sitting in a holding tank for a few days?