B1if db unexplained growth

New install of SAP 8.81.

4 companies installed: SBODemoUS, a renamed copy of SBODemoUS for report building, new company to hold live data with hardly anything in it, copy of same for testing. Only two active users, me in the reports db and client adding setup data to live system.

B1if grows at over a gig a day.

What could it be doing?

TIA