iCloud excess data use

Using more than 100 GB per 24 hour period when iCloud is enabled on this machine. Early 2009 Mac, new SSD. Any input from others would be appreciated.

You need to check to see what sort of options you have enabled as far what is being backed up to iCloud. Go to System Preferences->iCloud and explore everything there. Under iCloud Drive, you might have Desktop & Document folders checked which will backup everything to iCloud drive. BE AWARE if it is already checked and you uncheck it, it will DELETE the files locally. So make sure you have a backup of everything first and then copy those files to a separate folder for good measure before playing with the settings..