When you're using a sonotube in an open excavation, should you peel the sonotube off of your peirs before you backfill your hole? Or is it better to backfill, then only peel the sonotube off of what's above ground?
"Does the Sonotube form have to be stripped from the column after the concrete has cured?
Removal of the form is general practice for exposed column surfaces. In applications below grade, there is no specific need to strip the form unless it is required by local building code. The Sonotube Round form contains no hazardous chemicals and is biodegradable except for the 1-2 mil thick plastic liner on the inside of the form."
So, no. The reason to remove it is aesthetics, nothing more.