Must the starter double in quantity?

Must the starter double in quantity or is just an increase okay as long as it has lots of bubbles?

Steph

PS...Still looking for my Bluetooth adapter so I can post pics.  Can't find my cell phone charger either.  Oh brother, I do have issues, eh? ;-(

PS Update....found Bluetooth adapter and my charger ;-D  As soon as my phone has charged sufficiently, I'll post pics of my starters.